Mould germination: data treatment and modelling

The objectives of this study were i/ to examine germination data sets over a range of environmental conditions (water activity, temperature) for eight food spoilage moulds, ii/ to compare the ability of the Gompertz equation and logistic function to fit the experimental plots, iii/ to simulate germination by assessing various distributions of the latent period for germination amongst a population of spores. Data sets (percentage germination, P (%), versus time, t) of Aspergillus carbonarius, Aspergillus ochraceus, Fusarium verticillioides, Fusarium proliferatum, Gibberella zeae, Mucor racemosus, Penicillium chrysogenum and Penicillium verrucosum were analysed. No correlation, or relationship between the mean percentage [mean (P)] and the variance [var (P)] was found. Therefore no transformation of the germination data was required. Experimental data were fitted by using the Gompertz equation P = A exp (-exp [mu(m) e/A (delta - t) + 1]) and the logistic function P = Pmax/(1 + exp (k (tau - t))). Based on the residual mean square error (RMSE), no model performed better than the other one. However, model parameters were generally determined more precisely with the logistic model than with the Gompertz one. The time course of fungal spore germination curves was simulated assuming different distributions of the latent period for germination, lag, amongst a population of spores. The growth rate of germ tubes was calculated by means of the relationship: lag x rate = k. For normal Gaussian distributions, germination curves were symmetrical with respect to the inflection point and should be modelled with the logistic function. Skewed distributions were capable of simulating an asymmetric germination curve that was fitted by the Gompertz model. Future studies should be conducted for assessing whether the distributions assumed in this paper are in accordance with the experimental distributions that are still unknown.     

Monitoring and remote failure detection of grid-connected PV systems based on satellite observations

Small grid-connected photovoltaic systems up to 5 kW_p are often not monitored because advanced surveillance systems are not economical. Hence, some system failures which lead to partial energy losses stay unnoticed for a long time. Even a failure that results in a larger energy deficit can be difficult to detect by PV laymen due to the fluctuating energy yields.Within the EU project PVSAT-2, a fully automated performance check has been developed to assure maximum energy yields and to optimize system maintenance for small grid-connected PV systems. The aim is the early detection of system malfunctions and changing operating conditions to prevent energy and subsequent financial losses for the operator. The developed procedure is based on satellite-derived solar irradiance information that replaces on-site measurements. In conjunction with a simulation model the expected energy yield of a PV system is calculated. In case of the occurrence of a defined difference between the simulated and actual energy yield, an automated failure detection routine searches for the most probable failure sources and notifies the operator.This paper describes the individual components of the developed procedure—the satellite-derived irradiance, the used PV simulation model, and the principles of the automated failure detection routine. Moreover, it presents results of an 8-months test phase with 100 PV systems in three European countries.     

整体工程——将一个概念转变成能适应市场的终端产品

交钥匙工厂对许多纱线(化纤丝)制造商来说可以是空想,但它并不是不合实际的空想,如Oerlikon Barmag公司的设备规划工程部已清楚地证明了这一点。在挑选供货商这一阶段中,对企业客户来说,良好的服务起着越来越重要的作用。整套解决方案在安装和交付阶段能节省大量时间,能使生产过程最优化,并相应降低成本。     

Ligand Properties of N-Acyl-thiocarbamic-O-alkylesters – A new class of aza-analogous 1,3-thioxoketones

A series of six N-benzoyl-thiocarbamic-O-alkylesters (RMe, Et, i-Pr, Benzyl, n-Hex, n-Dodec; 1–6 ) has been prepared and characterized. They are weak monoprotic acids. The compounds behave as fairly stable and versatile bidentate (O,S)-chelating ligands towards multivalent metal ions e. g. Ni(II), Cu(II), Pb(II) the stability constants of which have been determined in 75 vol% dioxane/water. The molecular structure of bis(O-ethyl-N-benzoylthiocarbamato)nickel(II) 2a is presented. The coordination of the nickel atom is square planar with the two sulphur atoms in cis position.