A general expression for the relationship between induction period and supersaturation was
developed based on polynuclear approach. Different mechanism of primary nucleation in
solution can be illustrated by the expression. The results of induction period determined
by laser scattering method shows that the crystallization of ciprofloxacin hydrochloride
monohydrate in water/ethanol or aqueous solution is by the mechanism of primary nucleation
followed by one-dimensional diffusion growth, and then one-dimensional continuous or "birth
and spread"growth on crystal face. The growth mechanism on the crystal face is affected by
temperature and solvent.

The Large-eddy simulation (LES) with two-way coupling is used to study bubble-liquid two-
phase confined multiple jets discharged into a 2D channel. The LES results reveal the
large-eddy vortex structures of both liquid flow and bubble motion, the shear-generated and
bubble-induced liquid turbulence, and indicate much stronger bubble fluctuation than that
of the liquid, the enhancement of liquid turbulence by bubbles. Both shear and bubble-
liquid interaction are important for the liquid turbulence generation in the case studied.

The gas-liquid flow field in a stirred tank with a Rushton disk turbine, including the
impeller region,was numerically simulated using the improved inner-outer iterative
procedure. The characteristic features of the stirred tank, such as gas cavity and
accumulation of gas at the two sides of wall baffles, can be captured by the simulation.
The simulated results agree well with available experimental data. Since the improved
inner-outer iterative algorithm demands no empirical formula and experimental data for the
impeller region, and the approach seems generally applicable for simulating gas-liquid
stirred tanks.

An investigation of the characteristics of flowrate transients within slug flow was
conducted in a largescale outdoor testing facility. The test section consisted of a 378 m
long, 7.62 cm diameter stainless steel pipe.Air and water were used as the test fluids. The
response to a change of flowrate of either phase or two phases was measured using a series
of pressure transducers and differential pressure transducers. An increase or decrease in
gas flowrate caused a pressure overshoot above the value at new steady state or led to a
pressure undershoot to form a temporary stratified flow. Pressure waves existed in the
pipeline, spreading from the entrance to the exit. The magnitude of pressure overshoot in
"up-gas" transient or of pressure undershoot and period of the temporary stratified flow in
"Down-gas" transient are related to the change of gas flowrate and the distance away from
the entrance. In contrast, the change in liquid flowrate was accommodated by smooth
transitions between the corresponding steady states, and only one obvious change was found
in the slug frequency. According to experimental results, the pressure overshoot, pressure
undershoot and the pressure wave propagation were analyzed,and the phenomena were explained
reasonably. Some correlations for the calculation of the pressure overshoot and undershoot
were proposed.

Wall-liquid mass transfer for Taylor bubbles rising through liquid column in vertical tubes
is an important and fundamental topic in industrial processes. In this work, the
characteristics of wall-liquid mass transfer for this special case of slug flow were
studied experimentally by limiting diffusion current technique (LDCT). Based on the
experimental results and the analysis of hydrodynamic mechanisms, it was proposed that four
different zones exist, i.e. the laminar falling film zone, the turbulent falling film zone,
the wake region and the remaining liquid slug zone. The corresponding correlations for all
these zones were developed.

p-Aminobenzenesulfonic acid was selected as a typical solute with amphoteric functional
groups to be separated from dilute solution. A quaternary ammonium chloride, Aliquat 336,
was used as the extractant.The effects of pH, extractant concentration and diluent types on
distribution coefficient, D, were investigated.Meanwhile, the ion exchange reaction for
Aliquat 336 with p-aminobenzenesulfonic acid in the extraction process was discussed. The
description of D was proposed according to the mass action law. The results show that the D
in non-polar diluents, kerosene and CCl4, is larger than that in polar diluent, 1-octanol
and chloroform. The sodium sulfate in aqueous phase affects D strongly due to exchange of
sulfate ions with Aliquat 336. Finally, the removal of 4,4′-diaminostilbene-2,2′-
disulfonic acid (DSD acid), an amino sulfonic acid, was successfully achieved from
wastewater by the extraction with Aliquat 336.

An apparatus, designed to simulate bubbling of a sieve tray operated in froth regime, was
employed.Bubble contact angles in and above the incipient weeping regime for an air-water-
plexiglas system were investigated.The influence of both liquid cross-flow and gas up-flow
upon bubble contact angles was examined. A model considering the influence of liquid cross
-flow was developed to predict bubble size from a sieve hole in froth operation regime.The
comparison shows that the bubble sizes predicted by the present model are consistent with
our experimental values and the available published experimental data.

Five bacterial strains, which are able to grow and to disintegrate dibenzothiophene (DBT)
and dibenzothiophene sulfone (DBTO2) in fossil fuels, are isolated. Analysis of products of
DBT metabolized by these strains shows that different bacteria strains oxidize DBT by
different pathways. The isolated strains R-6, R-16, R-9 and R-8 can metabolize DBT to DBTO2
and 2-hydroxybiphenyl (HBP), which are identified as Bacillus brevis, Bacillus sphaericus,
Nocardia globerula and Pseudomonas delafieldii respectively. Another strain R-12 identified
as Pseudomonas sp. can degrade DBT completely but it cannot produce DBTO2 and HBP. The
optimum temperature and initial pH for desulfurization by R-8 are 32℃ and 7.02
respectively and pH of the broth decreases during biodegradation. The growth of strain R-8
with different sulfur-sources indicates that this strain in DBT medium has an induction
period of 3 days, which is longer than those with dimethylsulfoxide and MgSO4 media, but
the growth rate of the bacterial strain in DBT is higher after the induction. Higher growth
and desulfurization rates are observed in the DBT-hexadecane system than in both DBT-
ethanol and DBT-dimethylformamide systems. Both strains of R-8 and R-9 also show higher
desulfurization activities toward other sulfur-substrates, indicating that they have
greater desulfurization potential in application.

Three-layer feedforward networks have been widely used in modeling chemical engineering
processes and prior-knowledge-based methods have been introduced to improve their
performances. In this paper, we propose the methodology of designing better prior-
knowledge-based hybrid methods by combining the existing ones. Then according to this
methodology, two hybrid methods, interpolation-optimization (IO) method and
interpolationpenalty-function (IPF) method, are designed as examples. Finally, both methods
are applied to modeling two cases in chemical engineering to investigate their
effectiveness. Simulation results show that the performances of the hybrid methods are
better than those of their parents.

A type of wavelet neural network, in which the scale function is adopted only, is proposed
in this paper for non-linear dynamic process modelling. Its network size is decreased
significantly and the weight coefficients can be estimated by a linear algorithm. The
wavelet neural network holds some advantages superior to other types of neural networks.
First, its network structure is easy to specify based on its theoretical analysis and
intuition. Secondly,network training does not rely on stochastic gradient type techniques
and avoids the problem of poor convergence or undesirable local minima. The excellent
statistic properties of the weight parameter estimations can be proven here. Both
theoretical analysis and simulation study show that the identification method is robust and
reliable.Furthermore, a hybrid network structure incorporating first-principle knowledge
and wavelet network is developed to solve a commonly existing problem in chemical
production processes. Applications of the hybrid network to a practical production process
demonstrates that model generalisation capability is significantly improved.

The performance of UV/H2O2, UV/O3, and UV/H2O2/O3 oxidation systems for the treatment of
municipal solid-waste landfill leachate was investigated. Main objective of the experiment
was to remove total organic carbon (TOC), non-biodegradable organic compounds (NBDOC) and
color. In UV/H2O2 oxidation experiment,with the increase of H2O2 dosage, removal
efficiencies of TOC and color along with the ratio of biochemical oxygen demand (BOD) to
chemical oxygen demand (COD) of the effluent were increased and a better performance was
obtained than the system H2O2 alone. In UV/H2O2 oxidation, under the optimum condition H2O2
(0.2 time),removal efficiencies of TOC and color were 78.9% and 95.5%, respectively, and
BOD/COD ratio was significantly increased from 0.112 to 0.366. In UV/O3 oxidation, with the
increase of O3 dosage, removal efficiencies of TOC and color along with BOD/COD ratio of
the effluent were increased and a better performance was obtained than the system O3 alone.
Under the optimum condition UV/O3 (50 mg.min-1), removal efficiencies of TOC and color were
61.0% and 87.2%, respectively, and BOD/COD ratio was significantly increased from 0.112 to
0.323. In UV/H2O2/O3 system, color removal and BOD/COD ratio were improved further and TOC
removal efficiency was found to be 30.4% higher than the system UV/O3 without H2O2.

It is observed by scanning tunneling microscopy (STM) that the adsorbed Benzotriazole (BTA)
on copper is long in shape and has an irregular rectangle. The growth of BTA on copper is
in the form of polymeric chain and mainly in one dimension rather than two dimensions. The
copper surface covered by BTA becomes flatter,smoother and the roughness was smaller than
that of bare copper, so the corrosion is largely decreased. However,many grooves can be
seen between BTA polymeric chains in which corrosion may exist to a degree.

Excess molar volumes (VEm) of binary mixtures of 2-methyl-3-buten-2-ol [CH3C(OH)
(CH3)CHCH2]with four 1-alcohols: methanol, ethanol, 1-propanol and 1-butanol at 298.15 K
and atmospheric pressure are derived from density measurements with a vibrating-tube
densimeter. All the excess volumes are negative in the systems over the entire composition
range. The results are correlated with the Redlich-Kister equation. The effects of chain
length of 1-alcohols on VmE are discussed. The apparent molar volumes of 2-methyl-3-buten-
2-ol and 1-alcohols are calculated respectively.

The Vrentas-Duda free-volume theory has been extensively used to correlate or predict the
solvent diffusion coefficient of a polymer/solvent system. The energy term in the free
volume diffusion equation is difficult to estimate, so the energy term was usually
neglected in previous predictive versions of the free volume diffusion coefficient
equation. Recent studies show that the energy effect is very important even above the glass
transition temperature of the system. In this paper, a new evaluating method of the energy
term is proposed, that is, the diffusion energy at different solvent concentrations is
assumed to be a linear function of the solvent diffusion energy in pure solvents and that
in polymers under the condition that the solvent in infinite dilution. By taking
consideration of the influence of energy on the solvent diffusion, the prediction of
solvent diffusion coefficient was preformed for three polymer/solvent systems over a wide
range of concentrations and temperatures. The results show an improvement on the predictive
capability of the free volume diffusion theory.

Based on the concept of "element" and the fundamental thermodynamic principle, the
relationships of the residual properties, the property changes of mixing, excess
properties, fugacity coefficients and activity coefficients between the hypothetical
solution of elemental species and the equilibrated solution of actual species were
established. The hypothetical solution of elemental species provides a way of reducing the
dimensionality of problem, simplifying the analysis and visualizing the phase behavior.

Critical temperature (Tc) and critical pressure (pc) of the ternary mixture of ethylene +
benzene + ethylbenzene (the mole ratio of ethylbenzene to benzene was fixed at 0.95:0.05)
were measured by using a highpressure view cell with direct visual observation. The
interaction coefficients obtained from the critical properties of the relevant binary
systems were used to predict the critical properties (Tc, pc) of the ternary mixture. The
agreement between the prediction and experiments is satisfactory.

The critical properties of five compounds, including propanal, butanal, 1-pentanal, 2-
methel butanal and trimer of ethanal, were determined for the first time by a new capillary
quick-flow method. The apparatus was improved with a capillary tube and checked with hexane
and 1-heptene as standard reagents. The experimental results proved that the determination
of critical properties by quick-flow method with a capillary tube apparatus was successful.

The minimum fluid velocity to maintain particles just suspended was deduced, and the
theoretical analysis shows that the minimum velocity is influenced by the properties of the
solid and liquid, not by the operational conditions. For justification, the local minimum
velocity at the bottom of the tank was measured by a bi- electrode conductivity probe, in a
square-sectioned stirred tank (0.75m×0.75m×1.0m) with the glass beads-water system.The
experiments showed that the fluid velocities for the same suspension state were identical
despite that the power dissipated per unit mass was not the same under different
configuration and operation. Both theoretical analysis and experimental results indicate
that the off-bottom suspension is controlled by the local fluid flow over the bottom of the
stirred tank.

A new method, which correlates rate constants of chemical reactions and density or pressure
in supercritical fluids, was developed. Based on the transition state theory and
thermodynamic principles, the rate constant can be reasonably correlated with the density
of the supercritical fluid, and a correlation equation was obtained.Coupled with the
equation of state (EOS) of a supercritical solvent, the effect of pressure on reaction rate
constant could be represented. Two typical systems were used to test this method. The
result indicates that this method is suitable for dilute supercritical fluid solutions.

Bagasse fly ash was converted into an inexpensive adsorbent and utilized for the removal of
β-naphthalenesulfonic acid in dilute solution. The effect of pH, temperature, adsorbent
concentration, and co-existed acids on the removal ofβ-naphthalenesulfonic acid was
examined. The adsorption data have been correlated with both Langmuir and Freundlich
adsorption models. Thermodynamic parameters obtained indicate the feasibility of the
process, and kinetic studies provided the necessary mechanistic information of the removal
process.

A custom built dynamic oxygen uptake tester was used to study the influence of nitrogen
compounds on the oxidation characteristics of the saturate fractions from mineral base
oils. Experimental results indicate that nitrogen compounds, especially quinoline and
indole, take part in the oxidation of saturates. It is also found that indole is more
active than quinoline. The latter can be oxidized partly into ketoimine, and the former is
more rapidly oxidized into acylamide. The oxidation products, ketoimine or acylamide, could
inhibit the oxidation of the complex. For lower nitrogen content, the oxidation processes
were accelerated. However, at higher nitrogen content,the oxidation induction periods were
increased. The oxidation characteristics of saturates were also dependent on the type of
catalysts presented.

Lateral solid mixing was investigated experimentally in the dense zone of a 900mm×100mm×
5.2m rectangular circulating fluidized bed riser. Using heated tracer injection, the
lateral solid dispersion was determined by measuring the temperature response at different
lateral positions. Furthermore, a one-dimensional dispersion model, which describes the
solid mixing in the dense zone, is presented. The experimental results were used to
determine the lateral particle dispersion coefficient under various operating conditions. A
correlation of dispersion coefficient with bed height, gas velocity, and particle size is
also proposed.