2010 Chinese Control and Decision Conference, 2010
Considering the temporality of microbial fermentation process, a soft-sensing modeling method bas... more Considering the temporality of microbial fermentation process, a soft-sensing modeling method based on Continuous Hidden Markov Model (CHMM) for microbial fermentation process is proposed. Firstly, in order to improve the robustness of CHMM, multi-observation training sample sequences are used to train the CHMM. And the modified Baum-Welch parameters re-estimation formula is used to optimize the parameters of CHMM. Then, the new observation vector is inputed to the CHMM model library and the emission probability of each CHMM in the model library is calculated using the Viterbi Algorithm. Finally, the soft-sensing result can be obtained by computing the weighted average. The model is applied to an erythromycin fermentation process, and case studies show that the new approach has better performance compared to the conventional method based on ANN.
Thermal reaction rate constants have been determined for the reactions Cl+HI and Cl+HBr in the te... more Thermal reaction rate constants have been determined for the reactions Cl+HI and Cl+HBr in the temperature range 220–400 °K. The rates vary slowly with temperature. For Cl+HI the effective reaction cross section reaches a maximum of 31 Å2 near 300 °K. A tentative reaction model is proposed in which the attacking halogen atom is attracted to the halogen end of the hydrogen halide and then rotation of the hydrogen, with little or no activation energy, completes the reaction.
In an irregular sea, waves of different wavenumbers interact nonlinearly and give rise to second ... more In an irregular sea, waves of different wavenumbers interact nonlinearly and give rise to second order forces at the sum and difference frequencies. A moored or dynamically positioned vessel (ship or platform) can be induced to perform slow drift oscillations at the difference frequencies. To study the slow motion in a narrow- banded sea, the methods of multiple scales and matched asymptotics are combined. It is shown in general terms that slow drift motion is accompanied by long waves. The range of applicability of a formula for the wave force by Newman is discussed. An exception to the formula is a long body in beam seas with a small clearance under its keel. Some recent results for this case are presented, exhibiting resonant motion.
ABSTRACT Approximate equations for long waves are derived under assumptions similar to those of B... more ABSTRACT Approximate equations for long waves are derived under assumptions similar to those of Boussinesg and Korteweg and deVries. Numerical studies are performed using the method of characteristics. Four cases are investigated (1) solitary wave on a beach, (2) solitary wave on a shelf, (3) periodic waves generated in a wave tank of constant depth, (4) periodic wave on a shelf. It is discovered that complicated disintegration and evolution appear due to combined effects of nonlinearity and dispersion. Experimental evidence is presented. (Author)
Since the speed of sound in water is much greater than that of the surface gravity waves, acousti... more Since the speed of sound in water is much greater than that of the surface gravity waves, acoustic signals can be used for early warning of tsunamis. We simplify existing works by treating the sound wave alone without the much slower gravity wave, and derive a two-dimensional theory for signals emanating from a fault of finite length. Under the assumptions of a slender fault and constant sea depth, the asymptotic technique of multiple scales is applied to obtain analytical results. The modal envelopes of the two-dimensional sound waves are found to be governed by the Schrödinger equation and are solved explicitly. An approximate method is described for the inverse estimation of fault properties from the pressure record at a distant hydrophone.
With a general pressure gradient the boundary layer equations can be solved by a variety of moder... more With a general pressure gradient the boundary layer equations can be solved by a variety of modern numerical means. An alternative which can still be employed to simplify calculations is the momentum integral method of Karman. We explain this method for a transient boundary layer along the x-axis forced by an unsteady pressure gradient outside. This pressure gradient can be due to some unsteady and nonuniform flow such as waves or gust.
Motivated by potential applications for offshore airports supported on vertical piles, we report ... more Motivated by potential applications for offshore airports supported on vertical piles, we report a theory of wave diffraction by a periodic array of circular cylinders. The simple case of normal incidence on a rectangular array is studied here, which is equivalent to a line array along the centre of a long channel. An asymptotic theory is developed for cylinders much smaller than the incident wavelength, which is comparable to the cylinder spacing. Focus is on Bragg resonance near which scattering is strong. A combination of the method of multiple scales and the Bloch theorem leads to simple evolution equations coupling the wave envelopes. Dispersion of transient wave envelopes is investigated. Scattering of detuned waves by a large but finite number of cylinders is investigated for frequencies in and outside the band gap. Quantitative accuracy is assessed by comparisons with numerical computations via finite elements. The analytical theory prepares the ground for nonlinear studies ...
Waves and Nonlinear Processes in Hydrodynamics, 1996
Many papers have been devoted to nonlinear waves on a thin layer of viscous fluid flowing down an... more Many papers have been devoted to nonlinear waves on a thin layer of viscous fluid flowing down an incline at low to moderate Reynolds numbers (see Chang 1994 for a survey). Motivated by interests in chemical engineering, surface tension is emphasized in past studies where the Weber number W e is ususally assumed to be large W e = O(∈—2) where ∈ = is a small parameter denoting the depth-to-wavelength ratio. Among the few papers on high Reynolds numbers, the boundary layer approximation to O(∈2) accuracy and the momentum integral method are used for analytical convenience. Due to the complexity of these nonlinear evolution equations, most reported studies concentrate on permanent (or stationary) waves which propagate at a constant speed without changing form. However in these papers there exist inconsistencies since pressure is taken to be only hydrostatic which implies omission of 0(e 2) terms in the transverse momentum equation. A consistent second order theory has been worked out for large Reynolds numbers and small-to-moderate surface tension (Lee, 1995, Lee & Mei, 1995).
I. Some initial value problems are studied regarding the radiation and scattering of gravity wave... more I. Some initial value problems are studied regarding the radiation and scattering of gravity waves by finite bodies in an infinitely deep ocean. Emphasis is placed on the case where a finite number of thin plates lie on a vertical line, for which the general solution is obtained by transforming the boundary value problem to one of the Riemann-Hilbert type. Explicit investigations are made for the large time behavior of the free surface elevation for the case of a rolling plate, and for the Cauchy-Poisson problems in the presence of a stationary plate. By taking the limit as t → ∞, the steady state solution is derived for a harmonic point pressure acting on the free surface near a vertical barrier. Finally a formal asymptotic representation of the free surface elevation is given for large time when the geometry of the submerged bodies is arbitrary. II. The subject gravity waves in the two dimensional flow of a vertically stratified fluid is investigated with regard to the dynamic eff...
2010 Chinese Control and Decision Conference, 2010
Considering the temporality of microbial fermentation process, a soft-sensing modeling method bas... more Considering the temporality of microbial fermentation process, a soft-sensing modeling method based on Continuous Hidden Markov Model (CHMM) for microbial fermentation process is proposed. Firstly, in order to improve the robustness of CHMM, multi-observation training sample sequences are used to train the CHMM. And the modified Baum-Welch parameters re-estimation formula is used to optimize the parameters of CHMM. Then, the new observation vector is inputed to the CHMM model library and the emission probability of each CHMM in the model library is calculated using the Viterbi Algorithm. Finally, the soft-sensing result can be obtained by computing the weighted average. The model is applied to an erythromycin fermentation process, and case studies show that the new approach has better performance compared to the conventional method based on ANN.
Thermal reaction rate constants have been determined for the reactions Cl+HI and Cl+HBr in the te... more Thermal reaction rate constants have been determined for the reactions Cl+HI and Cl+HBr in the temperature range 220–400 °K. The rates vary slowly with temperature. For Cl+HI the effective reaction cross section reaches a maximum of 31 Å2 near 300 °K. A tentative reaction model is proposed in which the attacking halogen atom is attracted to the halogen end of the hydrogen halide and then rotation of the hydrogen, with little or no activation energy, completes the reaction.
In an irregular sea, waves of different wavenumbers interact nonlinearly and give rise to second ... more In an irregular sea, waves of different wavenumbers interact nonlinearly and give rise to second order forces at the sum and difference frequencies. A moored or dynamically positioned vessel (ship or platform) can be induced to perform slow drift oscillations at the difference frequencies. To study the slow motion in a narrow- banded sea, the methods of multiple scales and matched asymptotics are combined. It is shown in general terms that slow drift motion is accompanied by long waves. The range of applicability of a formula for the wave force by Newman is discussed. An exception to the formula is a long body in beam seas with a small clearance under its keel. Some recent results for this case are presented, exhibiting resonant motion.
ABSTRACT Approximate equations for long waves are derived under assumptions similar to those of B... more ABSTRACT Approximate equations for long waves are derived under assumptions similar to those of Boussinesg and Korteweg and deVries. Numerical studies are performed using the method of characteristics. Four cases are investigated (1) solitary wave on a beach, (2) solitary wave on a shelf, (3) periodic waves generated in a wave tank of constant depth, (4) periodic wave on a shelf. It is discovered that complicated disintegration and evolution appear due to combined effects of nonlinearity and dispersion. Experimental evidence is presented. (Author)
Since the speed of sound in water is much greater than that of the surface gravity waves, acousti... more Since the speed of sound in water is much greater than that of the surface gravity waves, acoustic signals can be used for early warning of tsunamis. We simplify existing works by treating the sound wave alone without the much slower gravity wave, and derive a two-dimensional theory for signals emanating from a fault of finite length. Under the assumptions of a slender fault and constant sea depth, the asymptotic technique of multiple scales is applied to obtain analytical results. The modal envelopes of the two-dimensional sound waves are found to be governed by the Schrödinger equation and are solved explicitly. An approximate method is described for the inverse estimation of fault properties from the pressure record at a distant hydrophone.
With a general pressure gradient the boundary layer equations can be solved by a variety of moder... more With a general pressure gradient the boundary layer equations can be solved by a variety of modern numerical means. An alternative which can still be employed to simplify calculations is the momentum integral method of Karman. We explain this method for a transient boundary layer along the x-axis forced by an unsteady pressure gradient outside. This pressure gradient can be due to some unsteady and nonuniform flow such as waves or gust.
Motivated by potential applications for offshore airports supported on vertical piles, we report ... more Motivated by potential applications for offshore airports supported on vertical piles, we report a theory of wave diffraction by a periodic array of circular cylinders. The simple case of normal incidence on a rectangular array is studied here, which is equivalent to a line array along the centre of a long channel. An asymptotic theory is developed for cylinders much smaller than the incident wavelength, which is comparable to the cylinder spacing. Focus is on Bragg resonance near which scattering is strong. A combination of the method of multiple scales and the Bloch theorem leads to simple evolution equations coupling the wave envelopes. Dispersion of transient wave envelopes is investigated. Scattering of detuned waves by a large but finite number of cylinders is investigated for frequencies in and outside the band gap. Quantitative accuracy is assessed by comparisons with numerical computations via finite elements. The analytical theory prepares the ground for nonlinear studies ...
Waves and Nonlinear Processes in Hydrodynamics, 1996
Many papers have been devoted to nonlinear waves on a thin layer of viscous fluid flowing down an... more Many papers have been devoted to nonlinear waves on a thin layer of viscous fluid flowing down an incline at low to moderate Reynolds numbers (see Chang 1994 for a survey). Motivated by interests in chemical engineering, surface tension is emphasized in past studies where the Weber number W e is ususally assumed to be large W e = O(∈—2) where ∈ = is a small parameter denoting the depth-to-wavelength ratio. Among the few papers on high Reynolds numbers, the boundary layer approximation to O(∈2) accuracy and the momentum integral method are used for analytical convenience. Due to the complexity of these nonlinear evolution equations, most reported studies concentrate on permanent (or stationary) waves which propagate at a constant speed without changing form. However in these papers there exist inconsistencies since pressure is taken to be only hydrostatic which implies omission of 0(e 2) terms in the transverse momentum equation. A consistent second order theory has been worked out for large Reynolds numbers and small-to-moderate surface tension (Lee, 1995, Lee & Mei, 1995).
I. Some initial value problems are studied regarding the radiation and scattering of gravity wave... more I. Some initial value problems are studied regarding the radiation and scattering of gravity waves by finite bodies in an infinitely deep ocean. Emphasis is placed on the case where a finite number of thin plates lie on a vertical line, for which the general solution is obtained by transforming the boundary value problem to one of the Riemann-Hilbert type. Explicit investigations are made for the large time behavior of the free surface elevation for the case of a rolling plate, and for the Cauchy-Poisson problems in the presence of a stationary plate. By taking the limit as t → ∞, the steady state solution is derived for a harmonic point pressure acting on the free surface near a vertical barrier. Finally a formal asymptotic representation of the free surface elevation is given for large time when the geometry of the submerged bodies is arbitrary. II. The subject gravity waves in the two dimensional flow of a vertically stratified fluid is investigated with regard to the dynamic eff...
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