A condition-based maintenance policy for offshore wind turbines is presented in consideration of the maintenance uncertainty and the weather effect. In this paper, the offshore wind turbine is ...divided into four main assemblies—namely, the rotor, gearbox, generator, and pitch system. The support vector machine classification technique is implemented to analyze the failure information, which was collected from field data in China. According to the results of fault diagnosis and prediction, the assembly that reaches the corresponding maintenance threshold will be repaired. At the same time, a maintenance opportunity occurs for the rest of the components, and an optimized plan can be determined by arranging the maintenance combination and time. The calculated results indicate that the proposed condition-based maintenance policy is beneficial to reduce the maintenance expenditure of offshore wind turbines.
The existing maintenance strategies of offshore wind energy are reviewed including the specific aspects of condition-based maintenance, focusing on three primary phases, namely, condition monitoring, ...fault diagnosis and prognosis, and maintenance optimization. Relevant academic research and industrial applications are identified and summarized. The state of art, capabilities, and constraints of condition-based maintenance are analyzed. The presented research demonstrates that the intelligent-based approach has become a promising solution for condition recognition, and an integrated data platform for offshore wind farms is significant to optimize the maintenance activities.
Sordariomycetes
is one of the largest classes of
Ascomycota
and is characterised by perithecial ascomata and inoperculate unitunicate asci. The class includes many important plant pathogens, as well ...as endophytes, saprobes, epiphytes, and fungicolous, lichenized or lichenicolous taxa. The class includes freshwater, marine and terrestrial taxa and has a worldwide distribution. This paper provides an updated outline of the
Sordariomycetes
and a backbone tree incorporating asexual and sexual genera in the class. Based on phylogeny and morphology we introduced three subclasses;
Diaporthomycetidae, Lulworthiomycetidae
and
Meliolomycetidae
and five orders;
Amplistromatales
,
Annulatascales
,
Falcocladiales
,
Jobellisiales
and
Togniniales
. The outline is based on literature to the end of 2014 and the backbone tree published in this paper. Notes for 397 taxa with information, such as new family and genera novelties, novel molecular data published since the Outline of Ascomycota 2009, and new links between sexual and asexual genera and thus synonymies, are provided. The Sordariomycetes now comprises six subclasses, 28 orders, 90 families and 1344 genera. In addition a list of 829 genera with uncertain placement in
Sordariomycetes
is also provided.
In the process of studying the diversity of Xylariales in China, three species owning characteristics of Graphostromataceae were observed in China. Morphology of the described species with ...illustrations and their phylogeny based on regions of internal transcribed spacers (ITS), the second-largest subunit of the RNA polymerase II (
RPB2
), β-tubulin (
TUB2
) and α-actin (
ACT
) are provided. Two new species and one new record from China are identified. Morphologically,
Biscogniauxia glaucae
sp. nov. differs from
B. atropunctata
var.
maritima
,
B. citriformis
var.
macrospora, B. fuscella
and
B. mediterranea
by its stromata with raised margins, clear outlines, punctate ostioles openings and ascospores which are equilateral with broadly rounded ends, a straight spore-length germ slit on the more concave side, lacking appendages and sheathes.
Graphostroma guizhouensis
is identified as a new species based on the multi-gene phylogenetic tree.
Camillea broomeana
with scanning electron microscope description of ascospores is illustrated as a new record from China.
Cryptostroma
is proposed in
Graphostromataceae
based on molecular data.
Vivantia
is accepted in
Graphostromataceae
based on its morphological characteristics and
Nodulisporiurn
anamorphs which are similar to those of
Biscogniauxia
.
This paper presents a risk assessment method for a ship’s power system under the conditions of an engine room fire based on the expert comprehensive evaluation (ECE) method combined with the fuzzy ...fault tree analysis (FFTA) method. The composition of the main engine system in the engine room and the failure logic of each subsystem were analyzed, and the fuzzy fault tree of a ship engine room fire was constructed. The probability of system failure and the importance of basic events were calculated. The fire safety risk assessment model was established using the safety risk matrix. The risk assessment of a ship engine room fire was implemented. The results demonstrated that the fire frequency of the ship engine room was 5.232 × 10−6 h−1. The fire risk of the main engine fuel system was the highest. Fuel leakages from diesel supply tanks and heavy fuel oil tanks are the main cause of accidents. The proposed method eliminated the influence of incomplete statistics in the risk assessment process and improved the accuracy and credibility of the reassessment results.
Widespread drug resistance and limited antibiotics challenge the treatment of pathogenic bacteria, which leads to a focus on searching for new antimicrobial lead compounds. We found the endophytic ...fungus
MFLUCC14-0151 from the medicinal plant
had antibacterial activity for the first time. This work aimed to reveal the capacity of
MFLUCC14-0151 against foodborne pathogenic bacteria and identify its bioactive substances. Bioassay-guided isolation led to the discovery of six infrequent active monomers, including (10R)-Xylariterpenoid B (1), Xylariterpenoid C (2), Tricycloalternarene 1b (3), Tricycloalternarene 3b (4), Funicin (5) and Vinetorin (6) from MFLUCC14-0151 for the first time. The results of antibacterial tests showed that (10R)-Xylariterpenoid B and Xylariterpenoid C exhibited inhibitory activities against
with MIC values ranging from 99.21 to 100.00 μM, and against
with MIC values ranging from 49.60 to 50.00 μM. Tricycloalternarene 1b and Tricycloalternarene 3b showed inhibitory effects on
with MIC values ranging from 36.13 to 75.76 μM. Unexpectedly, Funicin and Vinetorin exhibited remarkable antagonistic activities against
with MIC values of 10.35 and 10.21 μM, respectively, and against
with MIC values of 5.17 and 20.42 μM, respectively. In conclusion, we suggest that the isolated compounds Funicin and Vinetorin may be promising lead compounds for natural antibacterial agents.
The essential oil, extracted from the Hmong medicine Blumea balsamifera (L.) DC. (BBO), is a purely natural wound repair agent. Its application has, however, been restricted due to its low solubility ...and high volatility properties. In this study, we have developed a nanoemulsion formulation to improve the characteristics of BBO. The particle size of the nanoemulsion was normally distributed, and 71% of its range was concentrated between 10-100 nm, with an average particle size of 62.8 nm and an encapsulation rate of 98%. After 7 days of application, the wound healing rate of the BBO nanoemulsion (BBO-NE) group was 1.5 times higher than that of the normal BBO group. Along with histological observations, nanoemulsion formulation has been demonstrated to significantly improve the efficacy of BBO for wound repair. In addition, inflammation-related TLR4, CD14 and IRAK-1 gene transcript levels were significantly reduced after the administration of BBO-NE compared to the BBO group, with downregulation of 47.8%, 35.7% and 57.8%, respectively, while the secretion of pro-inflammatory factors IL-6 and TNF-α was also significantly reduced by 83.8% and 32.7%, respectively, in the nanoformulation administration (BBO-NE) group compared to the BBO group. In contrast, the anti-inflammatory factor IL-10 was significantly increased by 4.2-fold. It was further found that the drug penetration per unit area increased significantly 6.30% to 19.5% at different time points after the application of the BBO-NE compared to the BBO. In conclusion, nano-formulation enhanced the drug penetration of the BBO, reduced inflammatory factors, increased the level of anti-inflammatory factors, and promoted collagen deposition, thereby accelerating wound repair.
An innovative methodology is proposed to identify potential risk factors and possible accident escalation consequences, and to determine the evolution of an accident from cause to consequence, ...thereby to identify the most probable path and discover key risk factors along the path rapidly. Based on the principle of a directed weighted complex network (DWCN), the bow-tie (BT) model, risk entropy and the improved ant colony optimization (IACO) algorithm are integrated into this methodology. First, the qualitative analysis of risk evolution based on the BT model is carried out. The evolution development based on accident suppression can be divided into two stages: accident precursor stage and accident evolution stage. Then, a new method for mapping BT into DWCN is proposed. Lastly, the shortest path analysis of risk evolution based on the IACO algorithm is carried out, fuzzy set theory (FST) is introduced to calculate the failure probability of risk factors, and risk entropy is used to represent the uncertainty of risk propagation. Thus, the IACO algorithm can be used to calculate the shortest path of risk evolution. The proposed method is applied to oil and gas leakages in the FPSO oil and gas processing system. The results show that it is an effective method to identify the shortest evolution path and the most vulnerable risk factors.
It is increasingly necessary to perform risk analysis in marine structures, to ensure system safety, as they are large and complex. In view of the shortcomings of failure mode and effect analysis ...(FMEA), a modified fuzzy TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution) approach is proposed that is based on fuzzy evidence reasoning (FER), and considers the risk factor rating and relative weight. The presented method is used to prioritize the risk of equipment failure modes for the floating production storage and offloading system (FPSO) oil and gas processing system. The subjective weights and objective weights of occurrence (O), severity (S), and detectability (D) have been considered comprehensively. The subjective experience of the experts and the objective information reflected by the O, S, and D ratings are all included in the weights, making the ranking results closer to reality. The results can be scientific references for decision-makers in risk identification.
There are many factors involved in the layout optimization of cabin equipment, and human factors should be considered in the early stage of layout design. Human reliability is an effective index to ...evaluate the probability of success of the human completion of tasks. In order to put forward the method of human reliability which is more suitable for the layout optimization of cabin equipment, the existing methods of human reliability analysis (HRA) are systematically studied. At the same time, taking HRA, equipment correlation and cabin balance as objective functions, the optimization problem of cabin equipment layout was quantified into a mathematical model. When solving the model, the visibility graph method was used to model the cabin path planning, and a solution platform for the optimization of cabin equipment layout was developed on the basis of a genetic algorithm. Finally, the developed platform was applied with a ship example, and the results before and after the layout optimization were displayed through a three-dimensional model. At the same time, equipment layout evaluation software was used to simulate the experimental results so as to compare the improvement of important parameters before and after the layout optimization.
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