Stabilizing effect of the cyclodextrins additive to spray-dried particles of curcumin/polyvinylpyrrolidone on the supersaturated state of curcumin

Although curcumin is considered to have various therapeutic effects, its use as a functional food or supplement is restricted owing to its low water solubility and bioavailability. To increase the solubility of curcumin in water, the use of polyvinylpyrrolidone (PVP) and vinylpyrrolidone-vinyl acetate copolymers with a pyrrolidone skeleton was noted to be promising. In particular, the bi-component formulations of curcumin/PVP prepared through spray drying exhibited an amorphous state in powder X-ray diffraction observations and temporally increased the apparent solubility of curcumin to over 5000 times that of untreated curcumin; nevertheless, after 24 h, the solubility decreased owing to the unstable supersaturated state of curcumin. The addition of α-cyclodextrin (α-CyD) in the bi-component curcumin/PVP formulation helped maintain the supersaturated state of curcumin, whereas the addition of β- and γ-CyD led to the collapse of the supersaturated state. The addition of α-CyD can likely help inhibit the nucleation and crystal growth of curcumin, through the interaction among the solubilized units of curcumin/PVP and α-CyD.     

Numerical simulation of detonation wave propagation through a rigid permeable barrier

The results of calculation of the detonation propagation in a porous medium for hydrogen-air mixture are presented. The porous medium was specified explicitly and consisted of sets of individual obstacles in the form of solid walls or the sets of finite-size plates. Various modes of detonation propagation depending on obstacle parameters are obtained: propagation in a cellular mode, stationary propagation with destruction of the cellular structure of the detonation front, propagation of a monotonically attenuating detonation wave with destruction of the cellular structure of the front. The possibility of reducing the detonation propagation velocity by replacing solid plates with finite-size ones was shown. The effect of the geometrical parameters of the plates and the step of it installation on the degree of detonation attenuation was estimated. It was determined that an increase in the number of plates leads to a stronger attenuation of the detonation.     

Topological preservation techniques for nonlinear process monitoring

This work proposes a novel approach for the offline development and online implementation of data-driven process monitoring (PM) using topological preservation techniques, specifically self-organizing maps (SOM). Previous topological preservation PM applications have been restricted due to the lack of monitoring and diagnosis tools. In the proposed approach, the capabilities of SOM are further extended so that all aspects of PM can be performed in a single environment. First for fault detection, using SOM's vector quantization abilities, an SOM-based Gaussian mixture model (GMM) is proposed to define the normal region. For identification, an SOM-based contribution plot is proposed to identify the variables most responsible for the fault. This is done by analyzing the residual of the faulty point and an SOM model of the normal region used in fault detection. The data points are projected on the model by locating the best matching unit (BMU) of the point. Finally, for fault diagnosis a procedure is formulated involving the concept of multiple self-organizing maps (MSOM), creating a map for each fault. This allows the ability to include new faults without directly affecting previously characterized faults. A Tennessee Eastman Process (TEP) application is performed on dynamic faults such as random variations, sticky valves and a slow drift in kinetics. Previous studies of the TEP have considered particular feed-step-change faults. Results indicate an excellent performance when compared to linear and nonlinear distance preservation techniques and standard nonlinear SOM approaches in fault diagnosis and identification.     

Growing topology representing network

This paper describes a method for finding the topology of a data distribution online using a new growing graph network architecture. Many growing neural networks for finding the topology of data online, such as the Growing Neural Gas, depend on the order and number of input data. For this reason, conventional methods have certain drawbacks: weakness to noise, generating redundant nodes, requiring a great deal of input data, and so on. The proposed method is robust with respect to these issues since it has been developed from the viewpoint of a generative model. This paper presents both the theory and an algorithm in this paper. Moreover, the effectiveness of the proposed method is shown by experiments comparing the proposed method with various growing graph networks.     

Boiling heat transfer characteristics of a sulfuric-acid flow in thermochemical iodine–sulfur cycle

The Japan Atomic Energy Agency has been conducting research and development on the thermo-chemical iodine–sulfur (IS) process, which is one of the most attractive water-splitting hydrogen production methods that uses nuclear thermal energy. The sulfuric acid decomposer is one of the key components of the IS process. The boiling heat transfer coefficients of sulfuric acid solutions are required to design the sulfuric acid decomposer. These coefficients were measured in aqueous solutions where the mole fraction of H₂O ranged from 0.17 to 0.37 (heat flux range from 16.9 kW/m² to 5.6 kW/m²) and compared with the empirical correlations formulated for binary mixtures. A combination of the Stephan–Körner correlation, using the empirical constant A₀ = 2.00, and the Nishikawa–Fujita correlation was used to predict the experimental results with an accuracy of ±10%.     

Mixture semisupervised principal component regression model and soft sensor application

Traditionally, data‐based soft sensors are constructed upon the labeled historical dataset which contains equal numbers of input and output data samples. While it is easy to obtain input variables such as temperature, pressure, and flow rate in the chemical process, the output variables, which correspond to quality/key property variables, are much more difficult to obtain. Therefore, we may only have a small number of output data samples, and have much more input data samples. In this article, a mixture form of the semisupervised probabilistic principal component regression model is proposed for soft sensor application, which can efficiently incorporate the unlabeled data information from different operation modes. Compared to the total supervised method, both modeling efficiency and soft sensing performance are improved with the inclusion of additional unlabeled data samples. Two case studies are provided to evaluate the feasibility and efficiency of the new method. © 2013 American Institute of Chemical Engineers AIChE J 60: 533–545, 2014     

十二烷基硫酸钠-波尔多液复合材料的制备及其抑菌增效性能

以悬浮率为评价手段,探究添加组分的种类、含量对波尔多液悬浮率的影响;通过抑菌圈实验评价复配产品的协同杀菌性能;通过模拟降水评价复配产品的抗冲刷性能。结果表明,添加十二烷基硫酸钠(SDS)0.3 g/L时,有效组分的颗粒呈现3~5μm的空心线团状结构,d(0.9)为77.306μm,最大悬浮率为90.1%;抑菌圈实验发现,复配波尔多液对葡萄白腐菌(Coniothyrium diplodiella)和苹果腐烂菌(Valsa mali)的抑制率分别为84.2%和82.5%。经过室内模拟降水实验发现,新型波尔多液在叶面上的附着性能明显提升。添加SDS的波尔多液中,提升有效组分的悬浮率有利于提升杀菌性能。     

曲匹地尔合成工艺的研究

以氨基碳酸胍和甲酸为原料加入环合剂POCl3和缩合剂DCC-HOBT,使反应时间缩短了,生成的中间体5-甲基-7羟基-1,2,4-三氮唑[1,5-a]嘧啶收率高,重结晶用新型复合溶剂在产率、质量与文献[1-2]相比有较大提高与改善,收率由61%[1-2]提高到75%。     

混合邻间对甲酚制备化工中间体的工艺研究

以介孔分子筛为催化剂,催化烷基化混合邻间对甲酚制备6-叔丁基邻甲酚、6-叔丁基间甲酚、2-叔丁基对甲酚混合液,并精馏获得三种叔丁基甲酚纯品。考查了催化剂用量、异丁烯用量、反应温度等反应条件对烷基化反应的影响,确定了最佳工艺条件。结果表明,催化剂为三混甲酚用量的2.0%(质量),异丁烯用量与三混甲酚用量之比为1.05∶1(摩尔比),最佳反应温度为95℃的反应条件下,三混甲酚的总转化率达到96.25%以上,反应液中目标产品含量达94.67%,产品选择性可达98.36%。精馏后,6-叔丁基邻甲酚、6-叔丁基间甲酚、2-叔丁基对甲酚三种产品的质量含量分别为99.75%、99.57%、99.54%。整个工艺过程安全环保,成本低,能耗低,收益高。