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最近Sprikk设计公司为YNNO咨询事务所设计了一个全新的办公环境。YNNO咨询事务所专门为客户的工作以及环境等方面提供创新的点子,他们运用自己的专业技能为客户服务,并且一贯秉承着"工作中的新方式(new ways of working)"的理     

Influence of the relative amounts of crystalline and amorphous phases on the mechanical properties of polyamide-6 nanocomposites

The relative amounts of amorphous and crystalline γ- and α-phases in polyamide-6 nanocomposites, estimated from the deconvolution of X-ray diffraction peaks using Gaussian functions, correlates with their mechanical, thermomechanical, and barrier properties. The incorporation of organoclay platelets (Cloisite 15A and 30B) induced the crystallization of the polymer in the γ form at expense of the amorphous phase, such that 1–2 wt % of Cloisite is enough to enhance the mechanical and the thermomechanical properties. However, higher nanofiller loads were necessary to achieve good barrier effects, because this property is mainly dependent on the tortuous path permeation mechanism of the gas molecules through the nanocomposite films. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Multi-objective steady state optimization of biochemical reaction networks using a constrained genetic algorithm

A hybrid genetic algorithm-based method to solve constrained multi-objective optimization problems is proposed. Considering operation around a steady state of a dynamical system, the task of the algorithm consists on finding a set of optimal, but constrained solutions. The method is exemplified on a (bio)chemical reaction network in Saccharomyces cerevisiae. In the steady state the model reduces to a system of non-linear equations which must be solved by a search method. This iterative search was integrated into a genetic algorithm in order to look up for optimal steady states. The basic idea is to use individuals of the genetic algorithm as starting points for the search algorithm. The optimization goal was to simultaneously maximize ethanol production and reduce metabolic burden. Two alternative kinetic approaches are compared to Michaelis Menten-type kinetics: a S-System and a generalized mass action model, both based on Power-Law kinetics.     

Effect of nano-sized bioactive glass particles on the angiogenic properties of collagen based composites

Angiogenesis is essential for tissue regeneration and repair. A growing body of evidence shows that the use of bioactive glasses (BG) in biomaterial-based tissue engineering (TE) strategies may improve angiogenesis and induce increased vascularization in TE constructs. This work investigated the effect of adding nano-sized BG particles (n-BG) on the angiogenic properties of bovine type I collagen/n-BG composites. Nano-sized (20–30 nm) BG particles of nominally 45S5 Bioglass^® composition were used to prepare composite films, which were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The in vivo angiogenic response was evaluated using the quail chorioallantoic membrane (CAM) as an model of angiogenesis. At 24 h post-implantation, 10 wt% n-BG containing collagen films stimulated angiogenesis by increasing by 41 % the number of blood vessels branch points. In contrast, composite films containing 20 wt% n-BG were found to inhibit angiogenesis. This experimental study provides the first evidence that addition of a limited concentration of n-BG (10 wt%) to collagen films induces an early angiogenic response making selected collagen/n-BG composites attractive matrices for tissue engineering and regenerative medicine.     

Empirical and diffusion models to describe water transport into chickpea (Cicer arietinum L.)

To describe water transport in a porous media, a mathematical model is usually used. Among the models available in the literature, empirical and diffusive ones can be cited. In this paper, Page and diffusion models are used to describe drying and soaking of chickpea. In addition, new empirical equation is proposed to describe the mentioned processes. According to the results, the two empirical models well describe drying and soaking, but the proposed one gives the best statistical indicators. The use of the diffusion model to describe the drying process makes it possible to determine the effective diffusivities (7.13 × 10^?11, 10.39 × 10^?11 and 13.78 × 10^?11 m² s^?1 for the drying air at 40, 50 and 60 °C, respectively) and also the activation energy associated with the process (27.9 kJ mol^?1).     

Interzonal air and moisture transport through large horizontal openings in a full-scale two-story test-hut: Part 1 – Experimental study

Moisture transport by convection through large horizontal openings in dwellings, such as staircases, could have significant impact on the level, variation and distribution of humidity in each zone of dwellings. Yet, most studies and simulation tools of heat, air and moisture transport in buildings do not consider nor properly model this phenomenon; the lack of experimental data is one of the main causes. The aim of this experimental investigation was to study the air and moisture transport through a horizontal opening in a full-scale two-story test-hut. This study extended the cases with buoyancy-driven flows that have been studied by a handful of existing investigations, to the cases of combined buoyancy airflows and mechanical ventilation and cases with warmer upper room than the lower rooms. The main investigated parameters were different ventilation strategies, ventilation rates, and temperature differences between the lower and upper rooms. In total, 20 cases were tested. Measurements of temperature, relative humidity and air velocity were carried out within both rooms and across the horizontal opening. The air and moisture exchange through the horizontal openings are investigated based on two quantities representing the phenomenon: (i) steady-state difference between the average humidity ratios of the two rooms at the end of the moisture generation period, and (ii) mass airflow rates through the opening. The results show that interzonal air and moisture exchanges through the horizontal openings are strongly linked to the temperature difference between the two rooms, and the mechanical ventilation significantly restricts the interzonal airflows in comparison with cases without mechanical ventilation.     

Amoxicillin degradation at ppb levels by Fenton's oxidation using design of experiments

A central composite factorial design methodology was employed to optimise the amoxicillin degradation using the Fenton's oxidation treatment. In this study, the variables considered for the process optimisation were the hydrogen peroxide and ferrous ion initial concentrations and the temperature, for an antibiotic concentration of 450 μg L^− 1 at pH = 3.5. This methodology also allowed assessing and identifying the effects of the different factors studied and their interactions in the process response. An appropriate quadratic model was developed in order to plot the response surface and contour curves, which was used to perform the process optimisation. From this study, it was concluded that ferrous ion concentration and temperature were the variables that most influenced the response. Under the optimal conditions (hydrogen peroxide concentration = 3.50-4.28 mg L^− 1, ferrous ion concentration = 254-350 μg L^− 1 and temperature = 20-30 °C), it was possible to achieve total amoxicillin degradation after 30 min of reaction.     

Solubility of uranium and thorium from a healing earth in synthetic gut fluids: A case study for use in dose assessments

The aim of this case study was to estimate the bioaccessibility of uranium (²³⁸U) and thorium (²³²Th) from a healing earth by analysing the solubility of these radionuclides in synthetic gastric and intestinal fluids. An easy applicable in vitro test system was used to investigate the fractional mobilization of the soil contaminants being potentially available for absorption under human in vivo conditions. These findings provided the basis for a prospective dose assessment. The solubility experiments were performed using two different in vitro digestion methods. The concentrations of ²³⁸U and ²³²Th in the solutions extracted from the soil were measured by inductively coupled plasma mass spectrometry (ICP-MS). The dissolved fractions in the synthetic gastrointestinal fluid ranged in average from 10.3% to 13.8% for ²³⁸U and from 0.3% to 1.6% for ²³²Th, respectively, depending on the digestion method. Subsequently, the committed effective doses from intake of ²³⁸U and ²³²Th after ingestion of the healing earth during 1 year were evaluated for adult persons. Thereby ingestion dose coefficients calculated as a function of bioaccessibility were used. The dose assessments ranged between 4.3 × 10⁻⁷-1.9 × 10⁻⁶ Sv y⁻¹ for ²³⁸U and 5.6 × 10⁻⁷-3.3 × 10⁻⁶ Sv y⁻¹ for ²³²Th, respectively. On the basis of the assumptions and estimations made, the present work indicates a relatively low radiation risk due to ²³⁸U and ²³²Th after internal exposure of the healing earth.