8,086 research outputs found

    Distinguishing RBL-like objects and XBL-like objects with the peak emission frequency of the overall energy spectrum

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    We investigate quantitatively how the peak emission frequency of the overall energy spectrum is at work in distinguishing RBL-like and XBL-like objects. We employ the sample of Giommi et al. (1995) to study the distribution of BL Lacertae objects with various locations of the cutoff of the overall energy spectrum. We find that the sources with the cutoff located at lower frequency are indeed sited in the RBL region of the Ī±roāˆ’Ī±ox\alpha_{ro}-\alpha_{ox} plane, while those with the cutoff located at higher frequency are distributed in the XBL region. For a more quantitative study, we employ the BL Lacertae samples presented by Sambruna et al. (1996), where, the peak emission frequency, Ī½p\nu _p, of each source is estimated by fitting the data with a parabolic function. In the plot of Ī±rxāˆ’logā”Ī½p\alpha_{rx}-\log \nu_p we find that, in the four different regions divided by the Ī±rx=0.75\alpha_{rx}=0.75 line and the logā”Ī½p=14.7\log \nu_p=14.7 line, all the RBL-like objects are inside the upper left region, while most XBL-like objects are within the lower right region. A few sources are located in the lower left region. No sources are in the upper right region. This result is rather quantitative. It provides an evidence supporting what Giommi et al. (1995) suggested: RBL-like and XBL-like objects can be distinguished by the difference of the peak emission frequency of the overall energy spectrum.Comment: 7 pages, 2 figure

    A Distributed Coordination Strategy for Heterogeneous Building Flexible Thermal Loads in Responding to Smart Grids

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    Air conditioning systems are promising energy flexibility resources for smart grids. However, buildings with various thermodynamics must be coordinated to utilize limited energy flexibility effectively. This study proposes a distributed coordination strategy to coordinate building flexible thermal loads of different characteristics for optimized utilization of energy flexibility in a scalable and distributed manner. It consists of two components:1) an average consensus-based distributed sensing scheme to estimate the average thermal state of charge (SoC) of multiple zones, and 2) a weighted consensus-based distributed allocation module to allocate the demand response (DR) tasks or limited energy resources to multiple zones, proportional to their thermal storage capacities and deviations to the average thermal SoCs. Both algorithms achieve their goals respectively by fully distributed means through a sparse network with neighbor-to-neighbor communication. The sufficient condition for converging the weighted consensus algorithm is also derived for the first time. The proposed strategy is adopted for 1) weighted DR participation of residential inverter air conditioners and 2) weighted water flow redistribution of the commercial building water heating systems under urgent DR events. Simulation results show that adopting the distributed coordination strategy avoids the early depletion of demand flexibility resources and nonuniform thermal comfort sacrifices under uncoordinated control

    Ridge subduction and crustal growth in the Central Asian Orogenic Belt: Evidence from Late Carboniferous adakites and high-Mg diorites in the western Junggar region, northern Xinjiang (west China)

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    The Central Asian Orogenic Belt (CAOB) is a natural laboratory for the study of accretionary tectonics and crustal growth owing to its massive generation of juvenile crust in the Paleozoic. There is a debate, however, on the mechanism of this growth. In the Baogutu area of the western Junggar region, northern Xinjiang (west China), dioriteā€“granodiorite porphyry plutons and dikes are widely associated with Cuā€“Au mineralization. In this study, we present new results of zircon Uā€“Pb geochronology, major and trace elements, and Srā€“Ndā€“Pbā€“Hf isotope analyses for two dioriteā€“granodiorite porphyry plutons and two dikes from this area. LA-ICP-MS zircon Uā€“Pb analyses of four plutonic and dike samples yield Late Carboniferous ages of 315ā€“310 Ma. The Baogutu dioriteā€“granodiorite porphyries exhibit low-Fe and calc-alkaline compositions.They are also characterized by high Sr (346ā€“841 ppm) contents, low Y (9.18ā€“16.5 ppm) and Yb (0.95ā€“1.60 ppm) contents, and relatively high Sr/Y (31ā€“67) ratios, which are similar to those of typical adakites. In addition, some samples have relatively high MgO (2.35ā€“8.32 wt.%) and Mg# (48ā€“75), and Cr (22.7ā€“291 ppm) and Ni (32.0ā€“132 ppm) values, which are similar to those of high-Mg andesites. All rock samples exhibit mid-oceanic ridge basalt (MORB)-like Ndā€“Srā€“Pbā€“Hf isotope features: high ĪµNd(t) (+ 5.8ā€“+8.3) and ĪµHf(t) (+ 13.1ā€“+15.7) values, and relatively low (87Sr/86Sr)i (0.7033 to 0.7054) and (206Pb/204Pb)i (17.842ā€“18.055). The Baogutu adakitic rocks also contain reversely zoned clinopyroxene phenocrysts, which have low MgO cores and relatively high MgO rims. Geochemical modeling indicates that the Baogutu adakitic rocks could have been derived by mixing ~ 95% altered oceanic crust-derived melts with ~ 5% sediment-derived melts.Taking into account the regional geology, I- and A-type granitoids and Cuā€“Au mineralization, and the presence of Carboniferous ophiolite mĆ©langes in northern Xinjiang, we suggest that the Baogutu adakitic rocks were most probably generated by partial melting of a slab edge close to a subducting spreading ridge in the Late Carboniferous. Ridge subduction and the resultant slab window probably caused strong extension in the overlying lithosphere, extensive melting of subducting oceanic crust, mantle and juvenile lower crust, and interaction between slab-derived melts and the mantle. Thus, events associated with ridge subduction are likely to have played an important role in crustal growth in the CAOB in addition to previously recognized accretion of subduction and arc complexes and post-collisional crustal melting.Research Highlights ā–ŗNew constraints on ridge subduction in the Central Asian Orogenic Belt (CAOB). ā–ŗ315-310 Ma adakites and high-Mg diorites occur in the western Junggar region, CAOB. ā–ŗMajor and trace element, and Sr-Nd-Pb-Hf isotope data indicate slab melting. ā–ŗRidge subduction and the resultant slab window probably caused extensive melting. ā–ŗRidge subduction played an important role in crustal growth in the CAOB

    Soil CO2 efflux of a larch forest in northern Japan

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    Ā© The Authors, 2010. This article is distributed under the terms of the Creative Commons Attribution 3.0 License. The definitive version was published in Biogeosciences 7 (2010): 3447ā€“3457, doi:10.5194/bg-7-3447-2010.We had continuously measured soil CO2 efflux (Rs) in a larch forest in northern Japan at hourly intervals for the snow-free period in 2003 with an automated chamber system and partitioned Rs into heterotrophic respiration (Rh) and autotrophic respiration (Rr) by using the trench method. In addition, we applied the soil CO2 concentration gradients method to continuously measure soil CO2 profiles under snowpack in the snowy period and to partition Rs into topsoil (Oa and A horizons) CO2 efflux (Ft) with a depth of 0.13 m and sub-soil (C horizon) CO2 efflux (Fc). We found that soil CO2 effluxes were strongly affected by the seasonal variation of soil temperature but weakly correlated with soil moisture, probably because the volumetric soil moisture (30ā€“40% at 95% confidence interval) was within a plateau region for root and microbial activities. The soil CO2 effluxes changed seasonally in parallel with soil temperature in topsoil with the peak in late summer. On the other hand, the contribution of Rr to Rs was the largest at about 50% in early summer, when canopy photosynthesis and plant growth were more active. The temperature sensitivity (Q10) of Rr peaked in June. Under snowpack, Rs was stable until mid-March and then gradually increased with snow melting. Rs summed up to 79 gC māˆ’2 during the snowy season for 4 months. The annual Rs was determined at 934 gC māˆ’2 yāˆ’1 in 2003, which accounted for 63% of ecosystem respiration. The annual contributions of Rh and Rs to Rs were 57% and 43%, respectively. Based on the gradient approach, Rs was partitioned vertically into litter (Oi and Oe horizons) with a depth of 0.01ā€“0.02 m, topsoil and sub-soil respirations with proportions of 6, 72 and 22%, respectively, on an annual basis. The vertical distribution of CO2 efflux was consistent with those of soil carbon and root biomass.This work was supported by the Global Environmental Research Fund (B-073), Ministry of the Environment, Japan and Grants-in-Aid for Scientific Research (No. 13480150) from JSPS

    A hormone regulation based approach for distributed and on-line scheduling of machines and automated guided vehicles

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    [EN] With the continuous innovation of technology, automated guided vehicles are playing an increasingly important role on manufacturing systems. Both the scheduling of operations on machines as well as the scheduling of automated guided vehicles are essential factors contributing to the efficiency of the overall manufacturing systems. In this article, a hormone regulationĀæbased approach for on-line scheduling of machines and automated guided vehicles within a distributed system is proposed. In a real-time environment, the proposed approach assigns emergent tasks and generates feasible schedules implementing a task allocation approach based on hormonal regulation mechanism. This approach is tested on two scheduling problems in literatures. The results from the evaluation show that the proposed approach improves the scheduling quality compared with state-of-the-art on-line and off-line approaches.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research was sponsored by the National Natural Science Foundation of China (NSFC) under grant nos 51175262 and 51575264 and the Jiangsu Province Science Foundation for Excellent Youths under grant no. BK2012032. This research was also sponsored by the CASES project which was supported by a Marie Curie International Research Staff Exchange Scheme Fellowship within the 7th European Community Framework Programme under grant agreement no. 294931.Zheng, K.; Tang, D.; Giret Boggino, AS.; Salido, MA.; Sang, Z. (2016). A hormone regulation based approach for distributed and on-line scheduling of machines and automated guided vehicles. Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture. 232(1):99-113. https://doi.org/10.1177/0954405416662078S99113232

    Geochronology and geochemistry of Late Paleozoic magmatic rocks in the Lamasuā€“Dabate area, northwestern Tianshan (west China): Evidence for a tectonic transition from arc to post-collisional setting

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    Voluminous Late Paleozoic igneous rocks and associated Cuā€“Auā€“Mo deposits occur in the northwestern Tianshan district, Xinjiang, west China. However, the tectonic setting and petrogenesis of these rocks remain controversial. This paper reports zircon Uā€“Pb and Hf CUU isotopic data, major and trace elements, and Srā€“Ndā€“Pb isotopic data for the intrusive rocks and minor dacites in the Lamasuā€“Dabate area of northwestern Tianshan adjacent to the Cuā€“Auā€“Mo deposits. LA-ICPMS Uā€“Pb zircon analyses suggest that the Lamasu porphyries were formed at 366 Ā± 3 Ma and contain 907ā€“738 Ma inherited zircons, the Dabate dacites were formed at 316 Ā± 4 Ma, and granite porphyries were formed at 289 Ā± 3 Ma with ~ 319 Ma inherited zircons. The Lamasu porphyries consist of plagioclase granite and granodiorite, and are geochemically similar to adakites, e.g., having high Al2O3 (14.54ā€“19.75 wt.%) and Sr (308ā€“641 ppm) and low Y (7.84ā€“16.9 ppm) contents, with fractionated rare earth element (REE) patterns and slightly positive Sr anomalies.However, they have variable initial ratios of 87Sr/86Sr (0.7072ā€“0.7076) and 206Pb/204Pb (18.139ā€“18.450), and variable ĪµNd(t) (āˆ’ 5.6 to āˆ’ 0.8) and positive ĪµHf(t) (+ 1.4 to + 10.6) values. They also have variable Mg# (100 Ɨ Mg2+/(Mg2++ Fe2+)) (41ā€“73) and low Th (3.13ā€“8.09) and Th/Ce (0.14ā€“0.28) values. We suggest that the Lamasu adakitic magmas were generated through partial melting of southward subducted Junggar oceanic crust, with subsequent melt-mantle interaction and assimilation of basement rocks. The Dabate dacites show typical arc-like geochemical characteristics (e.g., enrichment of large ion lithophile elements (LILE) and strong negative anomalies of Ta, Nb, P and Ti), with variable ĪµNd(t) (+ 0.1 to + 3.3). They were probably generated by melting of juvenile basaltic lower crust as a result of magma underplating.The Dabate granite porphyries are geochemically similar to A2-type granites, e.g., high SiO2 (75.6ā€“77.6 wt.%) and alkalis (Na2O + K2O = 8.27ā€“8.70 wt.%), low CaO (0.28ā€“0.34 wt.%) and Mg# (2ā€“10), and obvious negative Eu, Ba and Sr anomalies. They have variable values of ĪµNd(t) (āˆ’ 1.7 to 0) and 206Pb/204Pbi (18.567ā€“18.721) and zircon ĪµHf(t) (+ 0.5 to + 11.1). The Dabate A-type granite porphyries contain Late Carboniferous residual zircon cores, suggesting that their source rock possibly contained Carboniferous arc igneous rocks. Taking into account all available data from Late Paleozoic magmatic rocks and Cuā€“Moā€“Au mineralization in the northern Tianshan district, we suggest that the Dabateā€“Lamasu area was a continental arc during the Late Devonianā€“Carboniferous but had entered a post-collisional stage by the Early-Permian (~ 290 Ma)

    Possible effects of probiotic strains on suppression of Vibrio and enhancement of growth in rotifer, Brachionus plicatilis

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    Because of the importance of rotifers as an adequate live food in larviculture, this study was conducted to evaluate probiotic potency of four microorganisms, Candida parapsilosis, Pseudoalteromonas flavipulchra, Lactobacillus sakei and Bacillus natto on suppression of Vibrio species and increasing population growth, enzymes activity and nutrients retention in the rotifer, Brachionus plicatilis. Four experimental and a control treatment, each with four replicates, with the concentration of 10(8) CFU/mL(-)(1) for each strain were applied. The results demonstrated that L. sakei and B. natto successfully suppressed Vibrio in experimental treatments and increased population growth and nutrients retention. The longevity of B. natto was recorded as the best in long-term inoculation than other treatments and the control in a way that after 8 days of rotifers starvation, the count of B. natto increased. The findings showed that the two bacteria, B. natto and L. sakei, appear to be a promising probiotic for rotifers in suppressing Vibrio and also in increasing population growth, nutrients retention, enzymes activity and long-term inoculation in rotifers
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