309 research outputs found
Measuring Learners’ Attitudes Toward Team Projects: Scale Development Through Exploratory And Confirmatory Factor Analyses
Team projects are increasingly used in engineering courses. Students may develop attitudes toward team projects from prior experience, and their attitudinal responses could influence their performance during team project-based learning in the future. Thus, instructors need to measure students’ attitudes toward team projects during their learner analysis to better understand students’ characteristics and be proactive in providing effective strategies to help students succeed in a team project environment. The purpose of our study was to develop a survey instrument that measures students’ attitudes toward team projects to be used as a learner analysis tool, derived from our local practical needs and due to the lack of appropriate existing instruments. The study was conducted at a mid-sized university in the northwestern United States during 2015-2016. After we generated an initial pool of 50 items, we administered the survey to 225 undergraduate engineering students, performed exploratory factor analysis on the data, and arrived at a four-factor solution of 20 items and a three-factor solution of 14 items. We tested the two competing solutions with another set of 330 undergraduate engineering students. Based on our confirmatory factor analysis results, we arrived at a three-factor model of 12 items as the finalized scale, which measures: (a) professional capacity building, (b) learning and problem-solving skills development, and (c) workload challenges. We call the scale, the Attitudes toward Team Projects Scale on Capacity, Learning, and Workload (ATPS-CLW). Suggestions for future research include continuous development, testing, and validation of the scale
Evolution of a First-Year Engineering Course
The first-year engineering course at Boise State University has evolved significantly over the past decade as a result of continuous improvement with a particular focus on student retention. The course was originally created in 1999-2001 as an “Introduction to Engineering” course in order to recruit students to one of the fields of engineering, by introducing those fields of engineering as topics across the semester. Over the first ten years, the course continued that introductory-to-field focus while also introducing a significant design element solving openended engineering problems. As a result of a five-year grant aimed toward improving first-year retention, the first-year course was substantially revised in 2013 to focus on developing mathematics skills, based on the work of Klingbeil and colleagues1–3. This paper describes these most recent modifications to the course and presents results from students who took the modified course as they moved forward in their academic careers and took second year mathematics and science courses. We collected data both in the form of grades and measurements of students’ self-efficacy to explore how increasing mathematical content in the first-year engineering class can improve students’ performance in both co-enrolled and subsequently enrolled mathematics and science courses
The interstellar oxygen-K absorption edge as observed by XMM-Newton
High resolution X-ray spectra of the Reflection Grating Spectrometer (RGS) on
board the XMM satellite are used to resolve the oxygen K absorption edge. By
combining spectra of low and high extinction sources, the observed absorption
edge can be split in the true interstellar (ISM) extinction and the
instrumental absorption. The detailed ISM edge structure closely follows the
edge structure of neutral oxygen as derived by theoretical R-matrix
calculations. However, the position of the theoretical edge requires a
wavelength shift. In addition the detailed instrumental RGS absorption edge
structure is presented. All results are verified by comparing to a subset of
Chandra LETG-HRC observations.Comment: LaTeX2e A&A style, 10 pages, 12 postscript figures, accepted for
publication in Astronomy and Astrophysic
Inactivation of mammalian Ero 1α is catalysed by specific protein disulfide isomerases
Disulfide formation within the endoplasmic reticulum is a complex process requiring a disulfide exchange protein such as protein disulfide isomerase and a mechanism to form disulfides de novo. In mammalian cells, the major pathway for de novo disulfide formation involves the enzyme Ero1α which couples oxidation of thiols to the reduction of molecular oxygen to form hydrogen peroxide. Ero1α activity is tightly regulated by a mechanism that requires the formation of regulatory disulfides. These regulatory disulfides are reduced to activate and reform to inactive the enzyme. To investigate the mechanism of inactivation we analysed regulatory disulfide formation in the presence of various oxidants under controlled oxygen concentration. Neither molecular oxygen, nor hydrogen peroxide was able to oxidise Ero1α efficiently to form the correct regulatory disulfides. However, specific members of the PDI family such as PDI or ERp46 were able to catalyse this process. Further studies showed that both active sites of PDI contribute to the formation of regulatory disulfides in Ero1α and that the PDI substrate binding domain is crucial to allow electron transfer between the two enzymes. These results demonstrate a simple feedback mechanism of regulation of mammalian Ero1α involving its primary substrate
ISICSoo: a class for the calculation of ionization cross sections from ECPSSR and PWBA theory
ISICS, originally a C language program for calculating K-, L- and M-shell
ionization and X-ray production cross sections from ECPSSR and PWBA theory, has
been reengineered into a C++ language class, named ISICSoo. The new software
design enables the use of ISICS functionality in other software systems. The
code, originally developed for Microsoft Windows operating systems, has been
ported to Linux and Mac OS platforms to facilitate its use in a wider
scientific environment. The reengineered software also includes some fixes to
the original implementation, which ensure more robust computational results and
a review of some physics parameters used in the computation. The paper
describes the software design and the modifications to the implementation with
respect to the previous version; it also documents the test process and
provides some indications about the software performance.Comment: Preprint submitted to Computer Physics Communication
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Application of Archimedes Filter for Reduction of Hanford HLW
Archimedes Technology Group, Inc., is developing a plasma mass separator called the Archimedes Filter that separates waste oxide mixtures ion by ion into two mass groups: light and heavy. For the first time, it is feasible to separate large amounts of material atom by atom in a single pass device. Although vacuum ion based electromagnetic separations have been around for many decades, they have traditionally depended on ion beam manipulation. Neutral plasma devices, on the other hand, are much easier, less costly, and permit several orders of magnitude greater throughput. The Filter has many potential applications in areas where separation of species is otherwise difficult or expensive. In particular, radioactive waste sludges at Hanford have been a particularly difficult issue for pretreatment and immobilization. Over 75% of Hanford HLW oxide mass (excluding water, carbon, and nitrogen) has mass less than 59 g/mol. On the other hand, 99.9% of radionuclide activity has mass greater than 89 g/mol. Therefore, Filter mass separation tuned to this cutoff would have a dramatic effect on the amount of IHLW produced--in fact IHLW would be reduced by a factor of at least four. The Archimedes Filter is a brand new tool for the separations specialist's toolbox. In this paper, we show results that describe the extent to which the Filter separates ionized material. Such results provide estimates for the potential advantages of Filter tunability, both in cutoff mass (electric and magnetic fields) and in degree of ionization (plasma power). Archimedes is now engaged in design and fabrication of its Demonstration Filter separator and intends on performing a full-scale treatment of Hanford high-level waste surrogates. The status of the Demo project will be described
On the reliability of the theoretical internal conversion coefficients
Possible sources of uncertainties in the calculations of the internal
conversion coefficients are studied. The uncertainties induced by them are
estimated.Comment: 16 pages (including 3 figures inserted by 'epsfig' macro
Discovery of X-rays from Venus with Chandra
On January 10 and 13, 2001, Venus was observed for the first time with an
X-ray astronomy satellite. The observation, performed with the ACIS-I and
LETG/ACIS-S instruments on Chandra, yielded data of high spatial, spectral, and
temporal resolution. Venus is clearly detected as a half-lit crescent, with
considerable brightening on the sunward limb. The morphology agrees well with
that expected from fluorescent scattering of solar X-rays in the planetary
atmosphere. The radiation is observed at discrete energies, mainly at the
O-K_alpha energy of 0.53 keV. Fluorescent radiation is also detected from
C-K_alpha at 0.28 keV and, marginally, from N-K_alpha at 0.40 keV. An
additional emission line is indicated at 0.29 keV, which might be the signature
of the C 1s --> pi* transition in CO_2 and CO. Evidence for temporal
variability of the X-ray flux was found at the 2.6 sigma level, with
fluctuations by factors of a few times indicated on time scales of minutes. All
these findings are fully consistent with fluorescent scattering of solar
X-rays. No other source of X-ray emission was detected, in particular none from
charge exchange interactions between highly charged heavy solar wind ions and
atmospheric neutrals, the dominant process for the X-ray emission of comets.
This is in agreement with the sensitivity of the observation.Comment: 12 pages, 9 figure
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Structural design of the DIII-D radiative divertor
The divertor of the DIII-D tokamak is being modified to operate as a slot type, dissipative divertor. This modification, called the Radiative Divertor Program (RDP) is being carried out in two phases. The design and analysis is complete and hardware is being fabricated for the first phase. This first phase consists of an upper divertor baffle and cryopump to provide some density control for high triangularity, single or double null discharges. Installation of the first phase is scheduled to start in October, 1996. The second phase provides pumping at all four divertor strike points of double null high triangularity discharges and baffling of the neutral particles from transport back to the core plasma. Studies of the effects of varying the slot length and width of the divertor can be easily accomplished with the design of RDP hardware. Static and dynamic analyses of the baffle structures, new cryopumps, and feedlines were performed during the preliminary and final design phases. Disruption loads and differential thermal displacements must be accommodated in the design of these components. With the full RDP hardware installed, the plasma current in DIII-D will be a maximum of 3.0 MA. Plasma disruptions induce toroidal currents in the cryopump, producing complex dynamic loads. Simultaneously, the vacuum vessel vibrations impose a sinusoidal base excitation to the supports for the cryopump. Static and dynamic analyses of the cryopump demonstrate that the stresses due to disruption and thermal loadings satisfy the stress and deflection criteria
Functional Relationship between Protein Disulfide Isomerase Family Members during the Oxidative Folding of Human Secretory Proteins
We systematically depleted PDI family members and show that whereas ERp72 and P5 contributed minimally to oxidative protein folding, PDI and ERp57 were the predominant catalysts. Depletion of PDI or ERp57 alone modestly delayed folding, but depletion of both led to generalized protein misfolding and degradation
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