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71.
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Anshuman Guha Hang Li Zhenguo Sun Chao Ma Dirk Werschmoeller Xiaochun Li 《Journal of Manufacturing Processes》2012,14(3):360-365
This paper presents the results of wireless data acquisition experiments from embedded micro thin film sensors in cutting inserts for machining. A bluetooth module is used to acquire data and establish communication with a receiver PC over the serial port profile (SPP). A signal conditioning circuit is designed and developed to increase the signal-to-noise ratio of the embedded micro thin film sensors. Moreover, an averaging filter algorithm is implemented as a software interface. To characterize the wireless data acquisition (DAQ) system, laser heating and turning tests are conducted. Both tests show that the wireless DAQ system is able to provide desirable capabilities as well as the wired one for the embedded thin film sensors in cutting inserts. 相似文献
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Microbial populations in tetra-distilled water collapsed when cultured in a permalloy chamber shielding the populations from the suns and earths electromagnetic field, but thrived when cultured in an ordinary thermostat open to the electromagnetic field. Theoretically, protons in liquid water can be excited at their natural resonance frequencies through Langmuir oscillations and obtain enough kinetic energy to charge the transmembrane potential of a cell. Microbes may be capable of converting this energy into chemical energy to supplement their energy needs. 相似文献
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Oliver V. Rattigan H. Dirk Felton Min-Suk Bae James J. Schwab Kenneth L. Demerjian 《Atmospheric environment (Oxford, England : 1994)》2010,44(16):2043-2053
Multi-year hourly measurements of PM2.5 elemental carbon (EC) and organic carbon (OC) from a site in the South Bronx, New York were used to examine diurnal, day of week and seasonal patterns. The hourly carbon measurements also provided temporally resolved information on sporadic EC spikes observed predominantly in winter. Furthermore, hourly EC and OC data were used to provide information on secondary organic aerosol formation. Average monthly EC concentrations ranged from 0.5 to 1.4 μg m?3 with peak hourly values of several μg m?3 typically observed from November to March. Mean EC concentrations were lower on weekends (approximately 27% lower on Saturday and 38% lower on Sunday) than on weekdays (Monday to Friday). The weekday/weekend difference was more pronounced during summer months and less noticeable during winter. Throughout the year EC exhibited a similar diurnal pattern to NOx showing a pronounced peak during the morning commute period (7–10 AM EST). These patterns suggest that EC was impacted by local mobile emissions and in addition by emissions from space heating sources during winter months. Although EC was highly correlated with black carbon (BC) there was a pronounced seasonal BC/EC gradient with summer BC concentrations approximately a factor of 2 higher than EC. Average monthly OC concentrations ranged from 1.0 to 4.1 μg m?3 with maximum hourly concentrations of 7–11 μg m?3 predominantly in summer or winter months. OC concentrations generally correlated with PM2.5 total mass and aerosol sulfate and with NOx during winter months. OC showed no particular day of week pattern. The OC diurnal pattern was typically different than EC except in winter when OC tracked EC and NOx indicating local primary emissions contributed significantly to OC during winter at the urban location. On average secondary organic aerosol was estimated to account for 40–50% of OC during winter and up to 63–73% during summer months. 相似文献
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The present study was carried out among a sample of 667 Dutch nurses and assesses three aspects of the construct validity of the two most widely used self-report burnout questionnaires: The Maslach Burnout Inventory (MBI) and the Burnout Measure (BM). Although the factorial validity of the three-dimensional structure of the MBI was convincingly demonstrated by confirmatory factor analysis with LISREL, four weak and ambiguous items were identified. Regarding the BM, some doubts have arisen about its one-dimensionality. The congruent validity of the questionnaires was well established: They both refer to the core element of the burnout syndrome (i.e. exhaustion). Moreover, linear structural analyses suggested that burnout is a two multi-dimensional construct consisting of an affective component (i.e. exhaustion) and an attitudinal component (i.e. a negative attitude towards recipients and towards one's job performance). However, the discriminant validity of the first component is rather poor since it considerably overlaps with self-reported somatic complaints and psychological strain. It is concluded that the MBI can be employed as a reliable and valid multi-dimensional indicator of burnout in professionals who work with people. The BM assesses the non-specific affective component of burnout (i.e. exhaustion) and should therefore be supplemented by a scale that measures the attitudinal component of the syndrome. 相似文献
80.
Ines Pöhler Dirk F. Wenderoth Katrin Wendt-Potthoff Manfred G. Höfle 《Water, Air, & Soil Pollution: Focus》2002,2(3):111-121
In an acid mining lake (pH 2.6) enclosure experiments wereperformed with the addition of different concentrations oforganic carbon, nitrogen and phosphorus. SSCP-communityfingerprints, based on 16S rRNA gene amplicons, were performed tomonitor changes in the structure of the total bacterialcommunity and the sulfate reducing bacteria (SRB) in themesocosms. Total bacterial cell counts, as assessed byepifluorescence microscopy, were increased in the mesocosmsamended with organic carbon. The addition of carbon alsoincreased the number of abundant bacterial taxa substantiallyalong depth. Sulfate reducing bacteria (SRB) could be detected inall enclosures and all parts of the water column. These SRBbelonged to genus Desulfobacter as indicated bycoroborating molecular data. 相似文献