杭州RAFFLES城

杭州Raffles城发展坐落于浙江省省会杭州市的钱塘江边，是嘉德置地继新加坡、上海、北京、成都和巴林之后的第六栋，将零售店、办公楼、住户和酒店设施融于一体，成为新城区的文化地标。     

On the use of stabilization techniques in the Cartesian grid finite element method framework for iterative solvers

Fictitious domain methods, like the Cartesian grid finite element method (cgFEM), are based on the use of unfitted meshes that must be intersected. This may yield to ill-conditioned systems of equations since the stiffness associated with a node could be small, thus poorly contributing to the energy of the problem. This issue complicates the use of iterative solvers for large problems. In this work, we present a new stabilization technique that, in the case of cgFEM, preserves the Cartesian structure of the mesh. The formulation consists in penalizing the free movement of those nodes by a smooth extension of the solution from the interior of the domain, through a postprocess of the solution via a displacement recovery technique. The numerical results show an improvement of the condition number and a decrease in the number of iterations of the iterative solver while preserving the problem accuracy.     

Analysis of a new type of high pressure homogeniser. A study of the flow pattern

High-pressure homogenisation is a key unit operation used to disrupt fat globules or cells containing intracellular bioproducts (AIChE J. 43(4) (1997) 1100). Modelling and optimisation of a small homogenising unit are often restrained by a lack of information on the flow conditions within the homogeniser valve. A numerical investigation of the flow within such a new homogenising valve, capable to reach pressure as high as (Stansted Fluid Power Ltd, UK) is presented. Results are obtained using the finite-volume technique and a RNG k-ε turbulence model with low Reynolds number near wall treatment conditions. An experimental measurement of the size of the valve gap is presented in order to validate mathematical relations that give valve gap sizes versus homogenising pressure. The modelling results give detailed information on the mechanical stresses and the high shear rates in small disruption valves, and also reveal other phenomena that could not be easily determined experimentally.     

PID control of MIMO process based on rank niching genetic algorithm

Non-linear multiple-input multiple-output (MIMO) processes which are common in industrial plants are characterized by significant interactions and non- linearities among their variables. Thus, tuning several controllers in complex industrial plants is a challenge for process engineers and operators. An approach for adjusting the parameters of n proportional–integral–derivative (PID) controllers based on multiobjective optimization and genetic algorithms (GA) is presented in this paper. A modified genetic algorithm with elitist model and niching method is developed to guarantee a set of solutions (set of PID parameters) with different tradeoffs regarding the multiple requirements of the control performance. Experiments considering a fluid catalytic cracking (FCC) unit, under PI and dynamic matrix control (DMC) are carried out in order to evaluate the proposed method. The results show that the proposed approach is an alternative to classical techniques as Ziegler–Nichols rules and others.     

Kinetic assessment and modeling of an ozonation step for full-scale municipal wastewater treatment: Micropollutant oxidation, by-product formation and disinfection

The kinetics of oxidation and disinfection processes during ozonation in a full-scale reactor treating secondary wastewater effluent were investigated for seven ozone doses ranging from 0.21 to 1.24 g O₃ g⁻¹ dissolved organic carbon (DOC). Substances reacting fast with ozone, such as diclofenac or carbamazepine (kP,O₃ > 10⁴ M⁻¹ s⁻¹), were eliminated within the gas bubble column, except for the lowest ozone dose of 0.21 g O₃ g⁻¹ DOC. For this low dose, this could be attributed to short-circuiting within the reactor. Substances with lower ozone reactivity (kP,O₃ < 10⁴ M⁻¹ s⁻¹) were only fully eliminated for higher ozone doses.The predictions of micropollutant oxidation based on coupling reactor hydraulics with ozone chemistry and reaction kinetics were up to a factor of 2.5 higher than full-scale measurements. Monte Carlo simulations showed that the observed differences were higher than model uncertainties. The overestimation of micropollutant oxidation was attributed to a protection of micropollutants from ozone attack by the interaction with aquatic colloids. Laboratory-scale batch experiments using wastewater from the same full-scale treatment plant could predict the oxidation of slowly-reacting micropollutants on the full-scale level within a factor of 1.5. The Rct value, the experimentally determined ratio of the concentrations of hydroxyl radicals and ozone, was identified as a major contribution to this difference.An increase in the formation of bromate, a potential human carcinogen, was observed with increasing ozone doses. The final concentration for the highest ozone dose of 1.24 g O₃ g⁻¹ DOC was 7.5 μg L⁻¹, which is below the drinking water standard of 10 μg L⁻¹. N-Nitrosodimethylamine (NDMA) formation of up to 15 ng L⁻¹ was observed in the first compartment of the reactor, followed by a slight elimination during sand filtration. Assimilable organic carbon (AOC) increased up to 740 μg AOC L⁻¹, with no clear trend when correlated to the ozone dose, and decreased by up to 50% during post-sand filtration. The disinfection capacity of the ozone reactor was assessed to be 1-4.5 log units in terms of total cell counts (TCC) and 0.5 to 2.5 log units for Escherichia coli (E. coli). Regrowth of up to 2.5 log units during sand filtration was observed for TCC while no regrowth occurred for E. coli. E. coli inactivation could not be accurately predicted by the model approach, most likely due to shielding of E. coli by flocs.     

Variability of Some Physico-chemical Characters in Desi and Kabuli Chickpea Types

A collection of 50 chickpea accessions (26 kabuli and 24 desi types) was evaluated for 2 years for eight physico-chemical seed characters: 100-seed weight, hydration capacity, hydration index, coat thickness and contents of protein, oil, acid detergent fibre (ADF) and starch. Significant differences were found between desi and kabuli types for the majority of the characters. The variance component due to the genotype×year interaction was important for the hydration index, starch and protein content, showing the importance of the year effect on genotypic expression of these characters. One kabuli accession and five desi accessions with high and stable protein content were selected. There was no overlap between the variation limits of desi and kabuli for coat thickness and ADF content. There were high positive and significant correlations between seed weight and oil content for both types of chickpea.     

Mechanical behavior of alumina and alumina-feldspar based ceramics in an acetic acid (4%) environment

This study investigates the mechanical properties of alumina-feldspar based ceramics when exposed to an aggressive environment (acetic acid 4%). Alumina ceramics containing different concentrations of feldspar (0%, 1%, 5%, 10%, or 40%) were sintered at either 1300, 1600, or 1700 °C. Flaws (of width 0%, 30%, or 50%) were introduced into the specimens using a saw. Half of these ceramic bodies were exposed to acetic acid. Their flexural strength, K_IC, and porosity were measured and the fractured samples were evaluated using scanning electronic- and optical microscopy. It was found that in the ceramic bodies sintered at 1600 °C, feldspar content up to 10% improved flexural strength and K_IC, and reduced porosities. Generally, it was found that acetic acid had a weakening effect on the flexural strength of samples sintered at 1700 °C but a beneficial effect on K_IC of ceramics sintered at 1600 °C. It was concluded that alumina-based ceramics with feldspar content up to 10% and sintered at higher temperatures would perform better in an aggressive environment similar to oral cavity.     

Überwachung von NSO-Heterocyclen an Teeröl-kontaminierten Standorten

In addition to well-characterized contaminants like homocyclic aromatic hydrocarbons, NSO-heterocyclic hydrocarbons typically occur at creosote-contaminated sites. Despite requirements by the German Federal Ordinance of Soil Protection to monitor NSO-heterocycles, this work has not routinely been done. Within the “KORA” project (“Natural Attenuation: Retention and Degradation Processes Reducing Contaminations in Groundwater and Soil”) funded by the German Federal Ministry of Education and Research, several creosote-contaminated sites were investigated. In conjunction with literature data on toxicity and persistence, priority substances were identified for inclusion in standard measurements for the evaluation of natural attenuation processes. Several analytical methods were developed for the detection and quantification of these compounds.     

Optical reflectance of metallic coatings: Effect of aluminum flake orientation

A set of aluminum-flake pigmented coatings having different flake orientations was prepared using various spraying conditions. The flake surface topography and the orientations of individual flakes were determined from images obtained by laser scanning confocal microscopy. Reflectance measurements were carried out to quantify the optical properties of the coatings. Both a Gaussian distribution (used to represent the measured flake orientation distribution) and a topographic map (including local surface roughness and orientation) of the flakes were then used as input to a ray scattering model to calculate the optical reflectance of each coatings Flake orientation distributions and examples of measured optical reflectance as a function of scattering angle are shown, and the latter are compared to calculated reflectance values. Presented at the 79th Annual Meeting of the Federation of Societies for Coatings Technology, in Atlanta, GA, Nov. 5–7, 2001. Gaithersburg, MD 20899. Louisville, KY 40211.