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31.
Fang-Chuan Lu Hann-Ming Henry Juang Chi-Chang Liao 《Meteorology and Atmospheric Physics》2007,95(1-2):27-52
Summary A numerical study of a cold surge that occurred from 19–23 December 2001 was conducted to better understand the cold surge
characteristics over the Taiwan area. The National Centers for Environmental Prediction (NCEP) nested Mesoscale Spectral Model
(MSM) was used for this study. Simulation results demonstrated that the nested NCEP MSM captured salient features of the selected
cold surge case. We demonstrated that the local minimum center of the time change of virtual potential temperature (dVPT)
can serve as the location of severe weather of the cold surge for all Taiwan regions. Furthermore, thermodynamic equation
analyses revealed that the leading edge of the cold surge was maintained primarily by meridian thermal advection, while diabatic
heating, vertical and zonal thermal advections were less important.
The cold surge flows were blocked and lifted by the Central Mountain Range (CMR) on its windward side, which increased the
cold surge’s vertical extent upward and increased northwestward tilting in the vertical structure. The flow eventually ascended,
switched direction toward Taiwan, and descended over its northwestern and eastern coasts. The physical and circulatory characteristics
of the cold surge differed noticeably on both sides of Taiwan. The cold surge’s leading edge over the Taiwan Strait was northeast-southwest
oriented and had evident wind shear; on the east side of the island, it was stronger in intensity and faster-moving than its
counterpart on the west side.
Sensitivity experiments revealed that the CMR’s trapping of cold surge flows on its windward side affected cold surge leading
edge characteristics in the following five ways: (1) weakening its intensity over the ocean but enhancing it inland, (2) decreasing
its southward speed, especially over the western low plains region, but increasing its movement on the east coast, (3) increasing
its vertical altitude and narrowing the horizontal extent of its vertical tilting, (4) altering its upper vertical circulatory
structure, and (5) trapping a V-shape density current and enhancing its intensity in connection with the land-sea contrast. 相似文献
32.
Employing harmonic analysis of tidal data in the Taiwan Strait, the cross-strait tidal characteristics are completely illustrated. Based on the two dimensional mild-slope equation which can be reduced to the shallow-water wave equation, a finite element model (Tsay et al., 1989) is applied to investigate the characteristics of tides in the Taiwan Strait. The co-range and equi-phase charts of major tidal constituents, such as M2, S2, N2, and K1, are reproduced. Anomalous amplification of semidiurnal tides in the Taiwan Strait is verified. With rotation effects neglected and by applying a non-reflective condition on the open boundaries, the numerical results of phase-lag and co-range distributions show very good agreement with observed data for semidiurnal tides in the Taiwan Strait. Due to crude representation of the topography at two ends along the China coast, computed tidal distributions deviate from the observations. However, both computed amplitudes and phase-lags compare very well with observed data along the central half of the China coast. 相似文献
33.
Electrogenic capabilities of gram negative and gram positive bacteria in microbial fuel cell combined with biological wastewater treatment 总被引：1，自引：1，他引：0
D. F. Juang Ph.D. P. C. Yang Ph.D. C. H. Lee Ph.D. S. C. Hsueh Ph.D. T. H. Kuo Ph.D. 《International Journal of Environmental Science and Technology》2011,8(4):781-792
The voltage and the power production of two gram negative and two gram positive bacteria in four identical continuous flow microbial fuel cells combined with biological wastewater treatment units were evaluated and compared in the present study. Each microbial fuel cell and biological treatment unit was operated at four different flow rates and four different external load resistances. The results show that overall removal efficiency of chemical oxygen demand for all four systems can reach more than 85.5 %. Each pure culture has different power generation performance that can be affected by some factors, such as wastewater characteristics, influent flow rate and hydraulic retention time of reactor. Good linear relationships between the flow rate and the potential and between the flow rate and the power density on four pure cultures at different external load resistances were found. Comamonas testosteroni has better power generation performance than Arthrobacter polychromogenes, especially at higher flow rate. Although Pseudomonas putida also showed higher power generation than Corynebacterium glutamicum, the difference was not statistically significant. It seems that gram negative bacteria could display higher power generation than gram positive bacteria at higher flow rate. However, more evidence is required to provide stronger proof for the difference of power generation between gram negative and gram positive bacteria. 相似文献
34.
D. F. Juang Ph.D. L. J. Chiou M.S. 《International Journal of Environmental Science and Technology》2007,4(1):119-125
Since Juang (2005) has found that the sludge settleability became much worse and the flocs displayed as pin flocs in only a few days after the addition of synthetic polymer was halted, it is hypothesized that the shift of microbial population in activated sludge before and after the addition of synthetic polymer might have occurred. Therefore, the identification of microbial population in the activated sludge of a lab-scaled continuous-flow type of treatment reactor was conducted at different phases of this study. The results of this study showed that the presence of synthetic polymer inhibited the growth of dominant bacteria and floc-formers in activated sludge, but gave a competitive advantage of growth to some other bacteria. The addition of synthetic polymer has caused the shift of microbial population and affected the growth of floc-formers in activated sludge. It took more than one month for the population structure of predominant microorganisms in activated sludge to return more closely to the initial population structure. 相似文献
35.
C. Hsein Juang Haiming Yuan Der-Her Lee Chih-Sheng Ku 《Soil Dynamics and Earthquake Engineering》2002,22(3)
In the early morning (1:47 Taiwan time) of September 21, 1999, the largest earthquake of the century in Taiwan (Mw=7.6, ML=7.3) struck this island country. The earthquake killed more than 2400 people and caused great destruction to buildings, bridges, dams, highways, and railways. One of the causes for heavy damages to the structures is soil liquefaction and ground settlement during the earthquake. In this paper, investigation of soil liquefaction and case histories of liquefaction are presented. Three CPT-based simplified methods, the Robertson method, the Olsen method, and the Juang method, are examined using the case histories derived from the Chi-Chi earthquake. The results of the comparison show that the Juang method is more accurate than the two methods in predicting liquefaction potential of soils based on the cases derived from the Chi-Chi earthquake, although all three methods are quite comparable in accuracy. 相似文献
36.
D. F. Juang W. P. Tsai W. K. Liu J. H. Lin 《International Journal of Environmental Science and Technology》2008,5(3):305-314
The objective of this study was to evaluate the treatment efficiency of a gravel contact oxidation treatment system which was newly constructed under the riverbed of Nan-men Stream located at the Shin Chu City of Taiwan. The influent and effluent water samples were taken periodically for the analyses of pH, temperature, dissolved oxygen, total suspended solids, five-day biological oxygen demand, NH4 +-N. The results showed that the average removal rates of five-day biological oxygen demand, total suspended solids and NH4 +-N were 33.6% (between ?6.7% and 82.1%), 56.3% (between ?83.0% and 93.4%) and 10.7% (between ?13.0% and 83.3%), respectively. The calculated mean first order reaction rate constant for five-day biological oxygen demand was 4.58/day with a standard deviation of 4.07/day and for NH4 +-N was 2.15/day with a standard deviation of 5.68/day. Therefore, it could be said that this gravel-contact-oxidation system could effectively remove biological oxygen demand, total suspended solids, and NH4 +-N in river water at a relatively short hydraulic retention time, although its pollutant treatment efficiency was not quite stable. However, to reach better or more stable treatment efficiency, aeration might sometimes be necessary to increase the dissolved oxygen in influent river water. And, longer hydraulic retention time of the system might also be required to increase NH4 +-N removal efficiency. 相似文献
37.
This paper presents some comparative design results of typical structural systems in accordance with various code provisions, such as UBC and ATC-03 of the U.S. and TJ-11–78 of China. The solution comparisons are based on an optimization scheme for a given set of constraints and objective functions. Three levels of recursive procedures are employed in the algorithm to search for an optimum weight or construction cost including damages. Numerical examples are provided to compare the design results based on the aforementioned code provisions. 相似文献
38.
Sara Khoshnevisan Lei Wang C. Hsein Juang 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2016,10(2):121-134
This paper provides a simplified procedure for reliability-based robust geotechnical design (RGD) using spreadsheet. In the RGD methodology, design robustness is achieved by adjusting “design parameters” without reducing the uncertainties in noise factors. This design approach generally involves a multi-objective optimisation, which is computationally challenging. To improve the efficiency of the RGD methodology, the design robustness is evaluated in terms of sensitivity index and the safety requirement is evaluated using mean value first order second moment (MFOSM). To ease the concern that the reliability index obtained with MFOSM may not be sufficiently accurate, a mapping function that relates MFOSM to a more accurate method such as first order reliability method is introduced. To further improve the efficiency of the proposed simplified RGD method, a new simplified procedure along with a more accurate robustness measure is developed that eliminates the need for multi-objective optimisation. With these modifications, the proposed simplified RGD method can efficiently be implemented in a single Excel spreadsheet. The proposed simplified method, which goes beyond any existing reliability-based RGD methods in terms of ease of use and computational efficiency, is illustrated in this paper with an example of robust design of drilled shaft in clay. 相似文献
39.
A neural fuzzy network approach to Radar pulse compression 总被引：1，自引：0，他引：1
Fun-Bin Duh Chia-Feng Juang Chin-Teng Lin 《Geoscience and Remote Sensing Letters, IEEE》2004,1(1):15-20
To make good range resolution and accuracy compatible with a high detection capability while maintaining the low average transmitted power, pulse compression processing giving low-range sidelobes is necessary. The traditional algorithms such as the direct autocorrelation filter (ACF), least squares (LS) inverse filter, and linear programming (LP) filter based on three-element Barker code (B13 code) have been developed. Recently, the neural network algorithms were issued. However, the traditional algorithms cannot achieve the requirements of high signal-to-sidelobe ratio and low integrated sidelobe level (ISL), and the normal neural networks such as the backpropagation (BP) network usually produce the extra problems of low convergence speed and are sensitive to the Doppler frequency shift. To overcome these defects, a new approach using a neural fuzzy network to deal with pulse compression in a radar system is presented. Two different Barker codes are carried out by a six-layer self-constructing neural fuzzy network (SONFIN). Simulation results show that this neural fuzzy network pulse compression (NFNPC) algorithm has significant advantages in noise rejection performance, range resolution ability, and Doppler tolerance, which are superior to the traditional and BP algorithms. 相似文献
40.
Jerome Peng-Yea Maa Cheng-Han Tsai Wen-Jye Juang Hsiang-Maw Tseng 《Ocean Dynamics》2011,61(4):411-423
New analysis of wave records at Hualien Harbor during Typhoon Tim in 1994 reveals that for certain wave periods, the ratios
of measured wave heights among three available wave stations inside the harbor are unique and roughly remain the same during
the severest period of resonance. Since there is no incident infragravity wave (period from 80 to 220 s) information at offshore
boundaries, these unique ratios become the surrogate of background truth for checking the performance of numerical simulations.
A new simulation effort using a large (45 × 17 km) modeling domain, high-resolution (20 × 20 m) grid and the RIDE wave transformation
model were conducted to simulate the observed responses. Comparison of the modeling results with the observations showed reasonable
agreement. Additional model studies using ideal bathymetries with the same grid domain and resolution were also conducted
to help interpret the prototype modeling results. The effects of two types of commonly used remedies were first examined by
using the ideal bathymetry, and then, the prototype bathymetry. The results demonstrated that a single 1-km long, shore-parallel
breakwater could significantly reduce the resonance. The results of using three shore-parallel breakwaters, however, are no
better. More studies to identify the optimum design associated with the shore-parallel breakwater (location, length, etc.)
are necessary for the optimum reduction of resonance at Hualien Harbor. 相似文献