A Bayesian Approach for Predicting Wind Turbine Failures based on Meteorological Conditions

With the growing wind energy sector, the need for advanced operation and maintenance (O&M) strategies has emerged. So far, mainly corrective or preventive O&M actions are applied. Predictive modelling, however, is expected to significantly enhance existing O&M practice. Here, anticipating wind turbine component failures can enable operators to lower the O&M cost and is particularly useful for wind farms located in remote areas or offshore locations. Previous research has shown that the failure behaviour of wind turbines and their components is highly influenced by the meteorological conditions under which the turbines operate. Hence, there is a significant need for robust models for failure prediction taking into consideration these conditions. Furthermore, solutions need to be found in order to determine the most suitable input variables for enhancing their prediction accuracy. This study uses failure data obtained from 984 wind turbines during 87 operational WT years. Bayesian belief networks (BBN) are trained based on failure records, technology specific covariates, as well as measurements of the environmental and operational conditions at site. Subsequently, the failure events in a wind farm during a period of 36 months are predicted with the BNN, whereas the failure events of six main components are predicted separately. Furthermore, an extensive sensitivity study is carried out to find the model with the highest prediction accuracy for each component. The influence of each meteorological, operational or technical covariate are discussed in detail. The models achieved a very good accuracy and were able to predict the majority of the component failures over the prediction period

Faculty Development at Small and Liberal Arts Colleges

The notable growth of faculty development programs and centers at small institutions warrants attention before their next stages of growth. We aim to capture and convey the central issues coalescing around the professionalization of teaching and learning activities and the work of faculty developers at small colleges. While this descriptive review draws direct comparisons to other types of institutions, particularly large research and comprehensive universities that serve as the norm for our profession’s faculty development practices, its main purpose is to address the distinctive characteristics of professional development at small colleges in general and liberal arts colleges in particular. Toward this end, we identify and explore four key issues: the characteristics and traditions related to teaching and learning in these institutional settings; the models and structures for teaching and learning programs at such colleges; the distinctive components of successful faculty development work at such institutions; and the broad applications that small college programs have for other institutional types and the future of our profession

SCADA alarms processing for wind turbine component failure detection

Wind turbine failure and downtime can often compromise the profitability of a wind farm due to their high impact on the operation and maintenance (O&M) costs. Early detection of failures can facilitate the changeover from corrective maintenance towards a pre- dictive approach. This paper presents a cost-effective methodology to combine various alarm analysis techniques, using data from the Supervisory Control and Data Acquisition (SCADA) system, in order to detect component failures. The approach categorises the alarms according to a reviewed taxonomy, turning overwhelming data into valuable information to assess component status. Then, different alarms analysis techniques are applied for two purposes: the evaluation of the SCADA alarm system capability to detect failures, and the investigation of the relation between components faults being followed by failure occurrences in others. Various case studies are presented and discussed. The study highlights the relationship between faulty behaviour in different components and between failures and adverse environmental conditions

Memory resources recover gradually over time: The effects of word frequency, presentation rate, and list composition on binding errors and mnemonic precision in source memory

Normative word frequency has played a key role in the study of human memory, but there is little agreement as to the mechanism responsible for its effects. To determine whether word frequency affects binding probability or memory precision, we used a continuous reproduction task to examine working memory for spatial positions of words. In three experiments, after studying a list of five words, participants had to report the spatial location of one of them on a circle. Across experiments we varied word frequency, presentation rate, and the proportion of low-frequency words on each trial. A mixture model dissociated memory precision, binding failure, and guessing rate parameters from the continuous distribution of errors. On trials that contained only low- or only high-frequency words, low-frequency words led to a greater degree of error in recalling the associated location. This was due to a higher word-location binding failure and not due to differences in memory precision or guessing rates. Slowing down the presentation rate eliminated the word frequency effect by reducing binding failures for low-frequency words. Mixing frequencies in a single trial hurt high-frequency and helped low-frequency words. These findings support the idea that word frequency can lead to both positive and negative mnemonic effects depending on a trade-off between an HF encoding advantage and a LF retrieval cue advantage. We suggest that (1) low-frequency words require more resources for binding, (2) that these resources recover gradually over time, and that (3) binding fails when these resources are insufficient

Assessing the Utility of Early Warning Systems for Detecting Failures in Major Wind Turbine Components

This paper provides enhancements to normal behaviour models for monitoring major wind turbine components and a methodology to assess the monitoring system reliability based on SCADA data and decision analysis. Typically, these monitoring systems are based on fully data-driven regression of damage sensitive-parameters. Firstly, the problem of selecting suitable inputs for building a temperature model of operating main bearings is addressed, based on a sensitivity study. This shows that the dimensionality of the dataset can be greatly reduced while reaching sufficient prediction accuracy. Subsequently, performance quantities are derived from a statistical description of the prediction error and used as input to a decision analysis. Two distinct intervention policies, replacement and repair, are compared in terms of expected utility. The aim of this study is to provide a method to quantify the benefit of implementing the online system from an economic risk perspective. Under the realistic hypotheses made, the numerical example shows for instance that replacement is not convenient compared to repair

Конформація пропоксазепаму та його орієнтація у центрі зв’язування ГАМКА-рецептора

Introduction. One of 1.4-benzodiazepine 3-alcoxy derivatives – propoxazepam, possessing high analgetic action, also effectively suppressed different experimental seizures types. Unexpected combination of pharmacological spectrum components suggests its different binding sites of GABAA receptor.The aim of the work was to determine the geometry of the ligand-receptor complexes of GABA-RC using experimental data of the propoxazepam conformation and calculated data for the three-dimensional structure of the ligandbinding site and subsequent docking to characterize its binding to this receptor.Materials and methods. X-ray diffraction studies of the compound were performed using Xcalibur 3 single crystal X-ray diffractometer. Calculation of the molecular docking parameters was performed using the iGEMDOCK v2.1 program for the GABA receptor (GABA (A) R-beta3 homopentamer, 4COF), the molecular structures of propoxazepam conformers were prepared using ChemAxon (MarvinSketch 17.11.0).Results and discussion. Based on the X-ray diffraction analysis, the coordinates of the atoms, bond lengths and valence angles in the propoxazepam molecule were calculated, it is found that it form crystallographic twins as racemate. The molecular docking method showed that propoxazepam several binding sites with the energy of complex formation from -78.64 to -85.29 kcal/mol exist on the isolated site of the GABA-receptor.Conclusions. The highest contribution to the formation of the bond of the complex is carried out by residues of polar amino acids (serine, asparagine, methionine and arginine in polar binding sub-center). However, also for individual conformers, aromatic amino acids, predominantly phenylalanine (Phe-31, Ala-135 – hydrophobic binding sub-center) make a significant contribution.Актуальность. Одно из 3-алкоксипроизводных 1,4-бенздиазепина – пропоксазепам – продемонстрировал высокую анальгетическую активность, а также эффективно блокировал разные типы экспериментальных судорог. Нестандартная комбинация компонентов фармакологического спектра предусматривает разные места его связывания на ГАМКА-рецепторе.Цель исследования состояла в определении геометрии лигандрецепторных комплексов ГАМК-РК на основе использования экспериментальных данных о конформации пропоксазепама и расчетных данных о трехмерном строении лигандсвязывающего центра и последующее проведение докинга для характеристики его связывания с данным рецептором.Материалы и методы. Рентгеноструктурное исследование соединения выполнено на монокристальном рентгеновском дифрактометре Xcalibur 3, Расчет параметров молекулярного докинга был осуществлен с использованием программы iGEMDOCK v2.1, для ГАМК-рецептора (GABA(A) R-beta3 гомопентамер, 4COF), молекулярные структуры конформеров пропоксазепама были подготовлены в программе ChemAxon (MarvinSketch 17.11.0).                                                                                              Результаты и их обсуждение. На основании данных рентгеноструктурного анализа рассчитаны координаты атомов, длины связей и валентные углы в молекуле пропоксазепама, установлено, что он существует в виде кристаллографического двойника в виде рацемата.                                      Выводы. Методом молекулярного докинга показано, что на выделенном участке ГАМКА-рецептора существует несколько мест связывания пропоксазепама с энергией образования комплекса от -78,64 до -85,29 ккал/моль. Наибольший вклад в формирование связи комплекса осуществляют остатки полярных аминокислот (серин, аспарагин, метионин и аргинин – полярный подцентр связывания). Однако также для отдельных конформеров значительный вклад имеют ароматические аминокислоты, преимущественно фенилаланин (Phe-31, Ala-135 – гидрофобный подцентр связывания).Актуальність. Одне з 3-алкоксипохідних 1,4-бенздіазепіну – пропоксазепам, який продемонстрував високу аналгетичну активність, а також ефективно блокував різні типи експериментальних судом. Нестандартна комбінація компонентів фармакологічного спектра передбачає різні місця його зв’язування на ГАМКА-рецепторі.Мета дослідження полягала у визначенні геометрії ліганд-рецепторних комплексів ГАМК-РК на підставі використання експериментальних даних про конформацію пропоксазепаму та розрахункових даних тривимірної будови лігандзв’язуючого центра та подальше проведення докінгу для характеристики його зв’язування з даним рецептором.Матеріали та методи. Рентгеноструктурне дослідження сполуки було виконано на монокристальному рентгенівському дифрактометрі Xcalibur 3, розрахунок параметрів молекулярного докінгу буз здійснений у програмі GEMDOCK v2.1, для ГАМК-рецептора (GABA(A) R-beta3 пентамер); молекулярні структури конформерів пропоксазепаму були підготовлені у програмі ChemAxon (MarvinSketch 17.11.0).Результати та їх обговорення. На підставі даних рентгеноструктурного аналізу розраховані координати атомів, довжини зв’язків та валентні кути у молекулі пропоксазепаму, встановлено, що він існує у вигляді кристалографічного двійника як рацемат.Висновки. Методом молекулярного докінгу показано, що на виділеній частині ГАМКА-рецептора існує декілька місць зв’язування пропоксазепаму з енергією утворення комплексів від -78,64 до -85,29 ккал/моль. Найбільший внесок у формування зв’язку комплексу здійснюють залишки полярних амінокислот (серин, аспарагін, метіонін та аргінін – полярний підцентр зв’язування). Однак також для окремих конформерів значний внесок мають ароматичні амінокислоти, переважно фенілаланін (Phe-31, Ala-135 – гідрофобний підцентр зв’язування)

Nutritional Evaluation and Physicochemical Properties of Fermented Shirezh Dairy Product

Many of the Kurdish traditional dairy products have not been studied thoroughly so far though are still produced at small scale. Dow (sour butter milk) and Shirezh are among these products. Shirezh known to Iraqi Kurds as sour concentrated Dow. The characteristics of Shirezh and Dow were: pH (5.5, 4.05), acidity (2.13%, 1.10%), total solids (18.70%, 5.32%), ash (0.62%, 0.45%), fat (2.57%, 0.8%) and total protein (13.59%, 3.28%) respectively, furthermore the amino acids of Shirezh’s protein found in balanced and acceptable quality. The aim of this research is to introduce Shirezh and Dow to scientific literature and to determine their characterization and nutritional values. Keywords: Shirezh, Dow, Dairy, Fermented, Nutrition, Physicochemical, Amino acids