890 research outputs found
Therblig-embedded value stream mapping method for lean energy machining
To improve energy efficiency, extensive studies have focused on the cutting parameters optimization in the machining process. Actually, non-cutting activities (NCA) occur frequently during machining and this is a promising way to save energy through optimizing NCA without changing the cutting parameters. However, it is difficult for the existing methods to accurately determine and reduce the energy wastes (EW) in NCA. To fill this gap, a novel Therblig-embedded Value Stream Mapping (TVSM) method is proposed to improve the energy transparency and clearly show and reduce the EW in NCA. The Future-State-Map (FSM) of TVSM can be built by minimizing non-cutting activities and Therbligs. By implementing the FSM, time and energy efficiencies can be improved without decreasing the machining quality, which is consistent with the goal of lean energy machining. The method is validated by a machining case study, the results show that the total energy is reduced by 7.65%, and the time efficiency of the value-added activities is improved by 8.12% , and the energy efficiency of value-added activities and Therbligs are raised by 4.95% and 1.58%, respectively. This approach can be applied to reduce the EW of NCA, to support designers to design high energy efficiency machining processes during process planning
Development of visualization facility at the GIS and Remote Sensing Core Lab, University of Nevada, Las Vegas
Visualization using advanced computational and graphic equipment has become a standard way of present day research. Availability of low cost and fast processing units, high resolution displays with graphic processing units, and specialized software has brought complex visualization capabilities to an office desktop. Nevertheless, when dealing with large datasets such as, global climate, geospatial, and social data the office desktop falls short and calls for a centralized visualization facility with high end computing and graphics equipment.
Visualization Facility at GIS and Remote Sensing Core Lab would be a useful and important addition to the UNLV IT infrastructure. It would provide multiple audio and video facilities for facilitating research, decision support, and collaboration. The video system would consist of a wide screen display capable to 3D and picture in picture visualization; and a tiled display wall. The audio system would consist of microphones and speakers. The backend management system will provide capability to route data from multiple sources to the video and audio systems. The sources would include local sources as well as remote sources from video teleconferencing.
UNLV Visualization Facility would provide an integration of visualization tools and expertise to provide researchers, decision makers, and policy makers with turn-key solutions to everyday visualization needs. This facility would be to provide the UNLV researchers ability to visualize concepts and data on a multi-screen/multi-projection system with the option to interactively study behaviors of models, data, and systems
New stilbenoids isolated from fungus-challenged peanut seeds and their bioactivity evaluations
Ph.DDOCTOR OF PHILOSOPH
Effects of Coronal Density and Magnetic Field Distributions on a Global Solar EUV Wave
We investigate a global extreme-ultraviolet (EUV) wave associated with a
coronal mass ejection (CME)-driven shock on 2017 September 10. The EUV wave is
transmitted by north- and south-polar coronal holes (CHs), which is observed by
the Solar Dynamics Observatory (SDO) and Solar Terrestrial Relations
Observatory A (STEREO-A) from opposite sides of the Sun. We obtain key findings
on how the EUV wave interacts with multiple coronal structures, and on its
connection with the CME-driven shock: (1) the transmitted EUV wave is still
connected with the shock that is incurvated to the Sun, after the shock has
reached the opposite side of the eruption; (2) the south CH transmitted EUV
wave is accelerated inside an on-disk, low-density region with closed magnetic
fields, which implies that an EUV wave can be accelerated in both open and
closed magnetic field regions; (3) part of the primary EUV wavefront turns
around a bright point (BP) with a bipolar magnetic structure when it approaches
a dim, low-density filament channel near the BP; (4) the primary EUV wave is
diffused and apparently halted near the boundaries of remote active regions
(ARs) that are far from the eruption, and no obvious AR related secondary waves
are detected; (5) the EUV wave extends to an unprecedented scale of ~360{\deg}
in latitudes, which is attributed to the polar CH transmission. These results
provide insights into the effects of coronal density and magnetic field
distributions on the evolution of an EUV wave, and into the connection between
the EUV wave and the associated CME-driven shock.Comment: 16 pages, 8 figures, and 3 animations available at
http://doi.org/10.13140/RG.2.2.12408.29442 ,
http://doi.org/10.13140/RG.2.2.25830.06723 , and
http://doi.org/10.13140/RG.2.2.19119.18088 ; published in Ap
Sun-to-Earth Characteristics of Two Coronal Mass Ejections Interacting near 1 AU: Formation of a Complex Ejecta and Generation of a Two-Step Geomagnetic Storm
On 2012 September 30 - October 1 the Earth underwent a two-step geomagnetic
storm. We examine the Sun-to-Earth characteristics of the coronal mass
ejections (CMEs) responsible for the geomagnetic storm with combined
heliospheric imaging and in situ observations. The first CME, which occurred on
2012 September 25, is a slow event and shows an acceleration followed by a
nearly invariant speed in the whole Sun-Earth space. The second event, launched
from the Sun on 2012 September 27, exhibits a quick acceleration, then a rapid
deceleration and finally a nearly constant speed, a typical Sun-to-Earth
propagation profile for fast CMEs \citep{liu13}. These two CMEs interacted near
1 AU as predicted by the heliospheric imaging observations and formed a complex
ejecta observed at Wind, with a shock inside that enhanced the pre-existing
southward magnetic field. Reconstruction of the complex ejecta with the in situ
data indicates an overall left-handed flux rope-like configuration, with an
embedded concave-outward shock front, a maximum magnetic field strength
deviating from the flux rope axis and convex-outward field lines ahead of the
shock. While the reconstruction results are consistent with the picture of
CME-CME interactions, a magnetic cloud-like structure without clear signs of
CME interactions \citep{lugaz14} is anticipated when the merging process is
finished.Comment: 15 pages, 5 figures. Accepted for publication in ApJ Letter
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