26,666 research outputs found

    EBW technology applied on the ICRF antenna component

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    Central conductor is one of the key components of ion cyclotron ranges of heating antenna, which is usually formed by welding due to the complex structures. High level of welding seam quality and small deformation are very important to central conductor. Electron beam welding (EBW) is suggested as the central conductor welding. To meet EBW requirements and reduce the risk, complex and high level of the accuracy welding fixture have been designed for central conductor EBW. Some samples were manufactured to do test and examination for EBW qualification before central conductor welding. Based on the welding parameters, thermal analysis using finite element method for the welding seam have been carried out. One mockup of central conductor for EBW has been made for proving welding parameters. In addition, some postwelding process were employed after one central conductor EBW. Results of examination and inspection of one central conductor using EBW are presented in this paper

    Regional and local contributions to ambient non-methane volatile organic compounds at a polluted rural/coastal site in Pearl River Delta, China

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    Identification of major sources of airborne pollutants and their contribution to pollutant loadings are critical in developing effective pollution control and mitigation strategies. In this study, a comprehensive dataset of non-methane volatile organic compounds (NMVOCs) collected from August 2001 to December 2002 at a polluted rural/coastal site in the Pearl River Delta (PRD) is analyzed to assess the relative contributions of major pollution sources to ambient NMVOC mixing ratios. A unique approach based on emission ratios of individual chemical species was used to classify the bulk air samples in order to apportion regional and local source contributions to the measured mixing ratios. The collected air samples fell into four major groups, including air masses from the inner PRD region and Hong Kong (HK) urban area. To estimate the source apportionment of NMVOCs, a principal component analysis/absolute principal component scores receptor model was applied to the classified data points. The results indicate that the regional and local source contributions to ambient NMVOC levels at the site were significantly different due to the differences in local versus regional energy use and industrial activities. For air masses originating from HK, vehicular emissions accounted for approximately 39% of the total NMVOC levels, followed by industrial emissions (35%), gasoline evaporation (14%) and commercial/domestic liquefied petroleum gas/natural gas use (12%). By contrast, for air masses originating from the PRD the industrial emissions accounted for 43% of the total NMVOC burden, followed by vehicular emissions (32%) and biomass burning (25%). In particular, the higher regional contribution of biomass burning found in this study as compared to existing emission inventories suggests that further efforts are necessary to refine the emission inventories of NMVOCs in the PRD region. © 2006 Elsevier Ltd. All rights reserved

    Measurements of trace gases in the inflow of South China Sea background air and outflow of regional pollution at Tai O, Southern China

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    We present a 16-month record of ozone (O3), carbon monoxide (CO), total reactive nitrogen (NOy), sulphur dioxide (SO2), methane (CH4), C2 - C8 non-methane hydrocarbons (NMHCs), C1 - C2 halocarbons, and dimethyl sulfide (DMS) measured at a southern China coastal site. The study aimed to establish/update seasonal profiles of chemically active trace gases and pollution tracers in subtropical Asia and to characterize the composition of the 'background' atmosphere over the South China Sea (SCS) and of pollution outflow from the industrialized Pearl River Delta (PRD) region and southern China. Most of the measured trace gases of anthropogenic origin exhibited a winter maximum and a summer minimum, while O3 showed a maximum in autumn which is in contrast to the seasonal behavior of O3 in rural eastern China and in many mid-latitude remote locations in the western Pacific. The data were segregated into two groups representing the SCS background air and the outflow of regional continental pollution (PRD plus southern China), based on CO mixing ratios and meteorological conditions. NMHCs and halocarbon data were further analyzed to examine the relationships between their variability and atmospheric lifetime and to elucidate the extent of atmospheric processing in the sampled air parcels. The trace gas variability (S) versus lifetime (τ) relationship, defined by the power law, Slnx = Aτ-b, (where X is the trace gas mixing ratio) gives a fit parameter A of 1.39 and exponent b of 0.42 for SCS air, and A of 2.86 and b of 0.31 for the regional continental air masses. An examination of ln[n-butane]/ln[ethane] versus ln[propane]/ln[ethane] indicates that their relative abundance was dominated by mixing as opposed to photochemistry in both SCS and regional outflow air masses. The very low ratios of ethyne/CO, propane/ethane and toluene/benzene suggest that the SCS air mass has undergone intense atmospheric processing since these gases were released into the atmosphere. Compared to the results from other polluted rural sites and from urban areas, the large values of these species in the outflow of PRD/southern China suggest source(s) emitting higher levels of ethyne, benzene, and toluene, relative to light alkanes. These chemical characteristics could be unique indicators of anthropogenic emissions from southern China. © Springer Science + Business Media, Inc. 2005

    Conjugate epipole-based self-calibration of camera under circular motion

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    In this paper, we propose a new method to self-calibrate camera with constant internal parameters under circular motion. The basis of our approach is to make use of the conjugate epipoles which are related to camera positions with rotation angles satisfying the conjugate constraint. A novel circular projective reconstruction is developed for computing the conjugate epipoles robustly. It is shown that for a camera with zero skew, two turntable sequences with different camera orientations are needed, and for a general camera three sequences with different camera orientations are required. The performance of the algorithm is tested with real images.published_or_final_versio

    unreinforced masonry buildings

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    A recent earthquake of M=4.9 occurred on 29 October 2007 in C, ameli, Denizli, which is located in a seismically active region at southwest Anatolia, Turkey. It has caused extensive damages at unreinforced masonry buildings like many other cases observed in Turkey during other previous earthquakes. Most of the damaged structures were non-engineered, seismically deficient, unreinforced masonry buildings. This paper presents a site survey of these damaged buildings. In addition to typical masonry damages, some infrequent, event-specific damages were also observed. Reasons for the relatively wide spread damages considering the magnitude of the event are discussed in the paper

    Source contributions to ambient VOCs and CO at a rural site in eastern China

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    Ambient data on volatile organic compounds (VOCs) and carbon monoxide (CO) obtained at a rural site in eastern China are analyzed to investigate the nature of emission sources and their relative contributions to ambient concentrations. A principal component analysis (PCA) showed that vehicle emissions and biofuel burning, biomass burning and industrial emissions were the major sources of VOCs and CO at the rural site. The source apportionments were then evaluated using an absolute principal component scores (APCS) technique combined with multiple linear regressions. The results indicated that 71%±5% (average±standard error) of the total VOC emissions were attributed to a combination of vehicle emissions and biofuel burning, and 7%±3% to gasoline evaporation and solvent emissions. Both biomass burning and industrial emissions contributed to 11%±1% and 11%±0.03% of the total VOC emissions, respectively. In addition, vehicle emissions and biomass and biofuel burning accounted for 96%±6% of the total CO emissions at the rural site, of which the biomass burning was responsible for 18%±3%. The results based on PCA/APCS are generally consistent with those from the emission inventory, although a larger relative contribution to CO from biomass burning is indicated from our analysis. © 2004 Elsevier Ltd. All rights reserved

    Design and Fabrication of Electrolyte-Supported Tubular SOFC Combined with Supercritical Water Oxidation on Biomass Gas

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    Solid oxide fuel cells (SOFCs) are relatively simple and environmental friendly devices for the production of electricity from hydrocarbons. The use of a high pressure supercritical water (SCW) reactor containing a SOFC has the potential for using a multitude of logistical liquid fuels that would otherwise not be possible in a regular SOFC system. A SOFC-SCW system was designed to allow the anode to be exposed to the pressure and chemical milieu of the supercritical water oxidation reactor. The effects of the amount of water/fuel and oxygen fed into the reactor under SCW conditions at 400 degrees C were studied. The effects on electrochemical performance as well as preliminary results on a number of feed stocks, for example pectin, are also described.open1111Nsciescopu

    Optimasi Penempatan Kapasitor pada Sistem Tegangan Menengah Regional Jawa Barat

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    When the inductive reactive load is higher, it will cause a voltage drop, increase the power losses in the system, decrease the power factor and decrease the capacity of the electrical power distribution. To reduce the load of inductive reactive power, a capacitive reactive power source is needed by installing the capacitor with the optimal size and at the right location. The method used to determine the optimal size and location of fuzzy logic-genetic algorithm. The parameters used in this simulation are minimal channel power losses while still meeting the specified voltage limit, Vmin = 0.95 PU and Vmax = 1.05 PU. The test results show that the location of the optimal capacitor placement with fuzzy logic-genetic algorithm is on bus 11 and bus 12. The test result from the study of newton raphson power flow, determining the location capacitor with fuzzy logic and determining the optimal capacitor size with genetic algorithm takes about 4 minutes.Ketika beban reaktif induktif semakin tinggi maka akan menyebabkan menurunnya tegangan, memperbesar rugi-rugi daya pada sistem, menurunnya faktor daya serta menurunnya kapasitas penyaluran daya listrik. Untuk mengurangi beban daya reaktif induktif diperlukan sumber daya reaktif kapasitif yaitu dengan memasang kapasitor dengan ukuran yang optimal dan pada lokasi yang tepat. Metode yang digunakan untuk menentukan ukuran dan lokasi optimal yaitu fuzzy logic-agoritma genetika. Parameter yang digunakan pada simulasi ini yaitu rugi-rugi daya saluran minimal dengan tetap memenuhi batas tegangan yang ditentuka yaitu voltage limit, Vmin= 0.95 PU dan PU and Vmax = 1.05 PU. Hasil pengujian menunjukan bahwa letak penempatan kapasitor yang optimal dengan fuzzy logic-algoritma genetika pada bus 11 dan bus 12. Hasil pengujian dari studi aliran daya dengan Newton-Raphson, penentuan letak kapasitor dengan logika fuzzy, dan optimasi ukuran kapasitor dengan algoritma genetika membutuhkan waktu sekitar 4 menit
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