Parameter identification of proton exchange membrane fuel cell via Levenberg-Marquardt backpropagation algorithm

It is essential to develop an accurate model of proton exchange membrane fuel cell (PEMFC) for a reliable operation and analysis, in which unknown parameters usually need to be determined. The inherent nonlinear, strong coupling, and diversification of PEMFC model seriously hinder traditional methods to identify the parameters. For the sake of overcoming these thorny obstacles, Levenberg-Marquardt backpropagation (LMBP) algorithm based on artificial neural networks (ANNs) is proposed for PEMFC parameter identification. Furthermore, the performance of LMBP is thoroughly evaluated and compared with four typical meta-heuristic algorithms under three cases. Simulation results indicate that LMBP performs a higher accuracy and faster speed for parameter identification. In particular, accuracy and convergence speed can achieve as much as 99.8% and 95.9% growth via LMBP, respectively.     

Misconceptions of human factors concepts

Abstract

Like many scientific topics, Human Factors, and Ergonomics concepts are susceptible to being misunderstood by people unfamiliar with the subject matter. Most of the time these misunderstandings are harmless, like when a safety poster within a work setting encourages employees to 'overcome complacency'. This misunderstanding of complacency suggests it is a motivational aspect of human behaviour correctable with encouragement, whereas the human factors approach to overcoming complacency would be to evaluate how task design could diminish the destructive consequences of unexpected changes within a routine setting. No harm comes from the message within the safety poster, other than some wasted ink and paper, but misconceptions among particular audiences can eventually result in dire consequences for the human operator. This paper presents recent evidence that the concepts are being misapplied by casual consumers of human factors, particularly in the aftermath of accidents within complex systems, in ways detrimental to the core mission of improving the well-being of the human operator. Later, because this special issue presents new ways to demonstrate value via return on investment, practical efforts we can take to overcome such misconceptions are suggested.     

A robust locating multi-optima approach for damage identification of plate-like structures

This paper proposes a robust optimization approach for multiple damage identification of plate-like structures. Different from traditional particle swarm optimizations (PSOs), a combined PSO and niche technique (NPSO) is proposed to solve multimodal optimization problems, with the full consideration of subswarm creation, merging and absorbing mechanism. As a hypersensitive parameter to damage, the curvature mode shape is adopted to construct the objective function. Case studies are conducted to investigate the effectiveness and robustness of the algorithm on multi-damage identification. Simulation results show that the proposed algorithm exhibits robust search performance on identifying damage locations accurately with good convergence behavior. It is hoped that this study can provide guidance on robust damage detection, especially when the structure is subject to multiple damages and external disturbances.     

Bioprospecting for brewers: Exploiting natural diversity for naturally diverse beers

The burgeoning interest in archaic, traditional, and novel beer styles has coincided with a growing appreciation of the role of yeasts in determining beer character as well as a better understanding of the ecology and biogeography of yeasts. Multiple studies in recent years have highlighted the potential of wild Saccharomyces and non-Saccharomyces yeasts for production of beers with novel flavour profiles and other desirable properties. Yeasts isolated from spontaneously fermented beers as well as from other food systems (wine, bread, and kombucha) have shown promise for brewing application, and there is evidence that such cross-system transfers have occurred naturally in the past. We review here the available literature pertaining to the use of nonconventional yeasts in brewing, with a focus on the origins of these yeasts, including methods of isolation. Practical aspects of utilizing nondomesticated yeasts are discussed, and modern methods to facilitate discovery of yeasts with brewing potential are highlighted.     

Nuclear DNA barcodes for cod identification in mildly-treated and processed food products

Gadoids are a group of fish with historical importance in the fishing industry. The high demand for cod is one of the reasons why cod products are often mislabelled, and numerous observations have been made on the replacement of Atlantic cod (Gadus morhua) by cheaper species or its illegal capture in contravention of fish quotas. Fish species identification is traditionally based on morphological features, but this may be difficult in case of heat-treated or processed products, or where the species look similar, as in the Gadoid group. DNA-based approaches (using either nuclear or mitochondrial DNA) are most commonly used in this case, due to their high specificity and to the high resilience of the target molecules to food processing techniques. In this article, we identified, using an automated screening approach, novel barcode regions and their associated primers in the nuclear genome, to be used for the efficient identification of Gadoids. The barcode regions were tested on official and commercial samples, raw or mildly treated products, like frozen, or salted, as well as pre-cooked complex mixtures and processed samples, using next-generation sequencing (NGS) technique. The method proposed could complement existing fish identification strategies in establishing an efficient framework to detect and prevent frauds along the food chain.     

Stability and antioxidant activity of anthocyanins from purple sweet potato (Ipomoea batatas L. cultivar Eshu No. 8) subjected to simulated in vitro gastrointestinal digestion

The study was aimed to investigate the stability and antioxidant activities of anthocyanins obtained from purple sweet potato via an in vitro digestion system. Three fractions of anthocyanin-rich extracts were obtained via ODS packing column. Anthocyanins and copigment (primary phenolic acids) of fraction 2 were investigated during simulated an in vitro gastrointestinal digestion. Anthocyanins and copigment were recognised by UPLC-LTQ-MS/MS. Besides, anthocyanins were found effectively stable under the acidic gastric digestion conditions. However, the anthocyanins recovery was greatly decreased at around 10% after intestinal digestion. An association between the type, number of acylated group and stability to intestinal digestion was found. Di-acylated anthocyanins possessed higher stability compared with mono-acylated anthocyanins and the stability of acylated group in digestion process followed the order of p-hydroxybenzoyl > feruloyl > caffeoyl. However, there was no much difference in copigment content which was found during digestion process. Moreover, the radical scavenging ability and xanthine oxidase (XO) inhibition showed that the digestion products possessed good biological activities mainly due to its anthocyanin composition.     

数字化核电厂班组SSA测度方法与实验研究

情景意识(SA)问题在数字化核电厂中更为突出。为识别班组共享情景意识（SSA）水平及行为形成因子（PSF）对班组SSA的影响，基于情景意识全面评估技术（SAGAT）建立一种班组SSA测量和计算方法并进行模拟机实验。结果表明，个体SA（ISA）水平与SSA水平有关，ISA级别越高，SSA级别越高；ISA和班组SSA都受到PSF的影响，PSF的状态水平越高，ISA和SSA的水平越高；对于不同的实验场景，操纵员的ISA水平和班组SSA水平不同，这表明风险场景的症状越明显及知识经验水平越好，ISA和SSA水平就越高。最后，通过被试的自评价识别当前PSF的状态水平，主要不良的PSF是班组沟通和合作水平、压力水平、人-机界面等。这些评估结果为提高数字化核电厂人因可靠性和安全水平提供了理论支持。