153 research outputs found
Learning styles, learning outcomes and course satisfaction: an investigation of a blended computer literacy course
This study examines the relationships among learning styles, learning outcomes and course satisfaction in a blended computer literacy undergraduate course at Iowa State University. Based on results from Kolb\u27s Learning Style Inventory (1999), participants were classified into one of four learning styles: Accommodator, Assimilator, Converger, or Diverger. The analyses of quantitative data (final grades, online survey) and qualitative data (interviews) indicated that there was little relationship between learning styles and learning outcomes as measured by final grades, or between learning styles and course satisfaction assessed from general feelings, communication and interaction, course organization, assessment, and weekly lab session in a blended learning environment. These findings support the research results as shown in Larsen (1992), Shih & Gamon (1999), and Wang, Hinn and Kanfer (2001). Quantitative data analysis showed a significant relationship between learning styles and course expectations, and between learning styles and the perceived value of the course schedule. Three students selected to represent three learning styles (all female) valued the blending of on-site labs with the web-based lecture component, whereas the only Converger interviewed (a male) did not value the blended on-site lab activities which complemented the web-based lecture component. This study suggests that blended learning offers a good opportunity to maximize students\u27 learning as stated by Singh (2003) and Thorne (2003)
Efficient Algorithms for Load Shuffling in Split-Platform AS/RS
We address the issue of shuffling loads in Automated Storage/Retrieval Systems (AS/RS) in this paper. The objective is to pre-sort the loads into any specified locations in order to minimize the response time of retrievals. 1D, 2D and 3D AS/RS racks have been designed in order to achieve the shuffling efficiently. The shuffling algorithms are described in detail. The response time of retrieval, the lower and upper bounds of energy consumption are also derived. Results of the analysis and numerical experiments show that the shuffling algorithms are quite efficient.Singapore-MIT Alliance (SMA
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Distinct Surface and Bulk Thermal Behaviors of LiNi0.6Mn0.2Co0.2O2 Cathode Materials as a Function of State of Charge.
Understanding how structural and chemical transformations take place in particles under thermal conditions can inform designing thermally robust electrode materials. Such a study necessitates the use of diagnostic techniques that are capable of probing the transformations at multiple length scales and at different states of charge (SOC). In this study, the thermal behavior of LiNi0.6Mn0.2Co0.2O2 (NMC-622) was examined as a function of SOC, using an array of bulk and surface-sensitive techniques. In general, thermal stability decreases as lithium content is lowered and conversion in the bulk to progressively reduced metal oxides (spinels, rock salt) occurs as the temperature is raised. Hard X-ray absorption spectroscopy (XAS) and X-ray Raman spectroscopy (XRS) experiments, which probe the bulk, reveal that Ni and Co are eventually reduced when partially delithiated samples (regardless of the SOC) are heated, although Mn is not. Surface-sensitive synchrotron techniques, such as soft XAS and transmission X-ray microscopy (TXM), however, reveal that for 50% delithiated samples, apparent oxidation of nickel occurs at particle surfaces under some circumstances. This is partially compensated by reduction of cobalt but may also be a consequence of redistribution of lithium ions upon heating. TXM results indicate the movement of reduced nickel ions into particle interiors or oxidized nickel ions to the surface or both. These experiments illustrate the complexity of the thermal behavior of NMC cathode materials. The study also informs the importance of investigating the surface and bulk difference as a function of SOC when studying the thermal behaviors of battery materials
Ultra-bright, ultra-broadband hard x-ray driven by laser-produced energetic electron beams
We propose a new method of obtaining a compact ultra-bright, ultra-broadband hard X-ray source. This X-ray source has a high peak brightness in the order of 1022 photons/(s mm2 mrad2 0.1\%BW), an ultrashort duration (10 fs), and a broadband spectrum (flat distribution from 0.1 MeV to 4 MeV), and thus has wide-ranging potential applications, such as in ultrafast Laue diffraction experiments. In our scheme, laser-plasma accelerators (LPAs) provide driven electron beams. A foil target is placed oblique to the beam direction so that the target normal sheath field (TNSF) is used to provide a bending force. Using this TNSF-kick scheme, we can fully utilize the advantages of current LPAs, including their high charge, high energy, and low emittance
Scheme for proton-driven plasma-wakefield acceleration of positively charged particles in a hollow plasma channel
A new scheme for accelerating positively charged particles in a plasma
wakefield accelerator is proposed. If the proton drive beam propagates in a
hollow plasma channel, and the beam radius is of order of the channel width,
the space charge force of the driver causes charge separation at the channel
wall, which helps to focus the positively charged witness bunch propagating
along the beam axis. In the channel, the acceleration buckets for positively
charged particles are much larger than in the blowout regime of the uniform
plasma, and stable acceleration over long distances is possible. In addition,
phasing of the witness with respect to the wave can be tuned by changing the
radius of the channel to ensure the acceleration is optimal. Two dimensional
simulations suggest that, for proton drivers likely available in future,
positively charged particles can be stably accelerated over 1 km with the
average acceleration gradient of 1.3 GeV/m.Comment: 16 pages, 4 figures, 25 reference
Characterization of genome-wide H3K27ac profiles reveals a distinct PM2.5-associated histone modification signature
Complete list of differentially modified H3K27ac loci. (XLSX 69 kb
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