Spall Fault Quantification Method for Flight Control Electromechanical Actuator

Flight control electro-mechanical actuators (EMAs) are among the primary onboard systems that significantly influence the reliability and safety of unmanned aerial vehicles. Recent reliability studies have shown that the ball-screw element of a flight control EMA is subject to oscillating operating conditions that may initiate rapid degradation, such as fatigue spall defects. Accordingly, detecting and quantifying such faults are crucial for developing efficient fault prognostic and remaining useful life estimation capabilities. In this study, a vibration-based fault quantification method is developed to quantify the fatigue faults of a ball-screw mechanism of an EMA. The method is based on identifying the ball passing instants through a localized surface defect on the vibrational jerk rather than the vibrational acceleration measurement. The jerk is numerically determined from conventional accelerometers using a Savitzky–Golay differentiator. This method was successfully tested for ball bearings and it is adjusted in this paper for ball-screw faults. The experimental validation is investigated on a set of fault-seeded samples on NASA’s Ames Research Center Flyable Electro-Mechanical Actuator test stand

Bmi1 Is Down-Regulated in the Aging Brain and Displays Antioxidant and Protective Activities in Neurons

Aging increases the risk to develop several neurodegenerative diseases, although the underlying mechanisms are poorly understood. Inactivation of the Polycomb group gene Bmi1 in mice results in growth retardation, cerebellar degeneration, and development of a premature aging-like phenotype. This progeroid phenotype is characterized by formation of lens cataracts, apoptosis of cortical neurons, and increase of reactive oxygen species (ROS) concentrations, owing to p53-mediated repression of antioxidant response (AOR) genes. Herein we report that Bmi1 expression progressively declines in the neurons of aging mouse and human brains. In old brains, p53 accumulates at the promoter of AOR genes, correlating with a repressed chromatin state, down-regulation of AOR genes, and increased oxidative damages to lipids and DNA. Comparative gene expression analysis further revealed that aging brains display an up-regulation of the senescence-associated genes IL-6, p19Arf and p16Ink4a, along with the pro-apoptotic gene Noxa, as seen in Bmi1-null mice. Increasing Bmi1 expression in cortical neurons conferred robust protection against DNA damage-induced cell death or mitochondrial poisoning, and resulted in suppression of ROS through activation of AOR genes. These observations unveil that Bmi1 genetic deficiency recapitulates aspects of physiological brain aging and that Bmi1 over-expression is a potential therapeutic modality against neurodegeneration

Physical Aspects of Cell Culture Substrates: Topography, Roughness, and Elasticity

The cellular environment impacts a myriad of cellular functions by providing signals that can modulate cell phenotype and function. Physical cues such as topography, roughness, gradients, and elasticity are of particular importance. Thus, synthetic substrates can be potentially useful tools for exploring the influence of the aforementioned physical properties on cellular function. Many micro‐ and nanofabrication processes have been employed to control substrate characteristics in both 2D and 3D environments. This review highlights strategies for modulating the physical properties of surfaces, the influence of these changes on cell responses, and the promise and limitations of these surfaces in in‐vitro settings. While both hard and soft materials are discussed, emphasis is placed on soft substrates. Moreover, methods for creating synthetic substrates for cell studies, substrate properties, and impact of substrate properties on cell behavior are the main focus of this review. The cellular environment plays a significant role in cell phenotype and function. As such, physical properties of cell culture substrates including topography, roughness, and elasticity may be utilized to investigate the influence of these physical cues on the cellular response. In this review, strategies for modulating the physical properties of surfaces, the influence of these changes on cell responses, and the promise and limitations of these surfaces in in‐vitro settings are highlighted, with a particular emphasis on elastic substrates.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90132/1/336_ftp.pd

Comparison of Leisure Attitude Levels of Oil Wrestling Athletes

Bu çalışmanın amacı, yağlı güreş sporcularının serbest zaman tutum düzeylerinin incelenmesi ve bazı demografik özelliklere göre karşılaştırılmasıdır. Çalışmanın evrenini, Türkiye Güreş Federasyonu’nun “baş”,“başaltı”,“büyük orta” ve “küçük orta büyük” yağlı güreşlerinde lisanslı olarak aktif olan yağlı güreş sporcuları oluşturmaktadır. Çalışma grubunu ise 2019 yılında yapılan “658. Tarihi Kırkpınar Yağlı Güreşleri”ne katılan sporculardan kolayda örneklem yöntemi ile seçilen 226 güreşçi arasından bilgi ve ölçek formlarını eksiksiz olarak dolduran, 18- 45 yaşları arasında değişen (Ortyaş=27.90 ± 7.05), 218 gönüllü oluşturmuştur. Çalışmada kullanılan veri toplama araçları 2 bölümden oluşmaktadır. Birinci bölüm, yağlı güreş katılımcılarının demografik bilgilerini tanımlamaya yönelik oluşturulan kişisel bilgi formu, ikinci bölümde ise araştırmanın amacına yönelik Boş Zaman Tutum Ölçeği (BZTÖ)’dir.Verilerin değerlendirilmesinde, tanımlayıcı istatistiklerle birlikte bağımsız örneklemler için MANOVA ve ANOVAanalizleri kullanılmıştır. Çalışma bulgularına göre yağlı güreş sporcularının serbest zaman tutumlarının yüksek olduğu ve “bilişsel” tutum alt boyutunun tüm boyutlar içerisinde en yüksek ortalama puanda olduğu, demografik değişkenlere göre; gelir,haftalık serbest zaman süresi ve serbest zamanları değerlendirmede güçlük çekme durum değişkenlerine göre farklılaştığı tespit edilmiştir. Sonuç olarak, ülkemizde asırlardır geleneksel olarak düzenlenen festivalin en önemli öğesi olan yağlı güreşçilerin, serbest zamanları değerlendirmeye ilişkin olarak spor federasyonları ve spor kulüpleri tarafından eğitimler ve çeşitli serbest zaman organizasyonları ile davranışsal tutumlarının yükseltilmesi için çalışmaların yapması önerilebilir.The aim of this study is to examine the leisure attitude levels of oil wrestling athletes and compare them according to some demographic features. The subject of the study is constituted by oil wrestling athletes who actively licensed in oil wrestling in Turkey Wrestling Federation's different catagories. The study group is constituted from 226 wrestlers who are ranging from 18-27 (apprx. =27.90 ± 7.05) years old and selected by the sampling method by filling accurately all the survey forms, which athletes participated in 2019's " 658. Historical Kırkpınar Oil Wrestling Competition". The data collection tools that are used in the study is formed by 2 parts. The first part is the personal information form to identify the demographic information of the oil wrestling participants. The second part is the Leisure Attitude Scale (LAS) according to the purpose of the study. Besides identifying statistics, MANOVA and ANOVA analyzes were used for independent samples and evaluation of the data. According to the findings of the study, it can be concluded that the leisure attitudes of the participants of the oil wrestling sports are high. The “cognitive” attitude subscale was the highest between the average score. According to the demographic variables, the income, weekly leisure period and the difficulty in assessing leisure are varied between the participants. As a result, regarding the evaluation of leisure time, it may be recommended for the sport federations and sport clubs to conduct studies to increase their behavioral attitudes through trainings and various leisure time organizations. The reason is that, this traditional oil wrestling competition in our country, which is organized for the centuries, is the most important element of the festiva

Fault detection and classification for flight control electromechanical actuators

Future aircraft architectures will incorporate more energy-efficient electromechanical actuators (EMA) for flight controls actuation. Development of reliable health monitoring techniques for EMAs promises to maintain or even increase the overall availability and safety of these new aircraft designs. When it comes to EMAs and similar mechanisms, certain fault types clearly manifest themselves through loss of functionality. Other faults, referred to as latent, do not immediately result in a significantly compromised actuator performance, thus making them challenging to detect. This paper presents a new vibration-based hybrid technique for detecting latent EMA faults without needing an initial stage of fault feature learning. The two faults considered in the study are a high-criticality jam and a low-criticality spall (metal flaking) in the actuator ballscrew mechanism. The actuator position is used to resample variable-speed vibration measurements of a single accelerometer into constant-rate measurements. A set of health characterization signatures is derived theoretically based on the EMA ballscrew kinematics. These theoretical signatures are compared with the signatures extracted from vibration signals measured experimentally on the EMA test articles. The vibration signatures approach is also compared to the diagnostic approach based on EMA motor current measurements. The ability to detect and classify latent faults early as high- or low-critical can improve maintenance planning and increase aircraft dispatch reliability. The technique has been validated on fault-injected data sets collected on the NASA Ames Research Center Flyable Electro-Mechanical Actuator (FLEA) test stand

INVESTIGATION OF THE PACKAGE TOURS ORGANIZED FROM TURKEY TO BALKAN PENINSULA (CASE OF BOSNIA AND HERZEGOVINA)

Turizm sektöründen elde edilen gelirlerin, ülke ekonomisinde gün geçtikçe önemli bir kaynak haline geldiği Bosna Hersek, Balkan Yarımadası’nda yer alan önemli turizm destinasyonları arasında yer almaktadır. Bu nedenle ülke, birçok Avrupa ülkesinin yanı sıra tarihsel ve kültürel bağları nedeni ile Türkiye’den de çok sayıda turisti çekmektedir. Bu çalışma ile Türkiye’den Balkan Yarımadası’na düzenlenen paket turlardan özellikle Bosna Hersek’in yer aldığı tur programlarının incelenmesi amaçlanmıştır. Çalışmanın ilk bölümünde, konuyla ilgili istatistiki verilerden faydalanılarak Bosna Hersek turizminin genel değerlendirilmesi yapılmıştır. Araştırmanın ikinci bölümünde ise, seyahat acentaları tarafından Türkiye’den Balkan Yarımadası’na düzenlenen paket turların içerikleri incelenmiş ve analiz edilmiştir. Böylece düzenlenen turların bir turistik ürün olarak detaylarının incelenmesi ve var olan tur programlarına ait içeriklerin geliştirilebilmesi için alternatif önerilerin ortaya konulması amaçlanmıştır. Araştırma kapsamında Türkiye’den Balkan Yarımadası’na düzenlenen 133 paket tur programının içerikleri internet ortamından yararlanarak incelenmiş ve söz konusu programlar; geceleme süresi, kullanılan ulaşım aracı, tur güzergahı, vize durumu ve kişi başı tur ücreti unsurları göz önünde bulundurularak Bosna Hersek’in Türk turistlerce tercih edilmesindeki öncelikler belirlenmiştir. Ayrıca, bu destinasyona düzenlenmekte olan turların eksiklikleri de farklı açılardan ele alınarak Bosna Hersek turizminin geliştirilmesine yönelik çözüm önerileri de sunulmuştur.Bosnia and Herzegovina is one of the important tourism destinations located in the Balkan Peninsula. The income from the tourism sector has become an important resource in national economy day by day in Bosnia and Herzegovina. Therefore this country has atttacted many tourists from many European countries and also Turkey due to their historical and cultural ties.This study has aimed to inverstigate the package tours which ara organized from Turkey to Balkan Peninsula and the tours especially with Bosnia and Herzegovina. In the first part of the using the statistical data on the subject. In the second part of the study, contents of the package tours from Turkey to Balkan Peninsula organized by travel agencies had been examined and analyzed. In this way, it has been aimed to investigate these tours alternative suggestions for improving of the corrent existing programs. Within the context of this been analyzed benefit from internet and priorities had been set in taking into consideration of overnight period, used in transport, tour route, visa statu and tour fee for per person elements

Spatio-temporal Weather Forecasting and Attention Mechanism on Convolutional LSTMs

Numerical weather forecasting on high-resolution physical models consume hours of computations on supercomputers. Application of deep learning and machine learning methods in forecasting revealed new solutions in this area. In this paper, we forecast high-resolution numeric weather data using both input weather data and observations by providing a novel deep learning architecture. We formulate the problem as spatio-temporal prediction. Our model is composed of Convolutional Long-short Term Memory, and Convolutional Neural Network units with encoder-decoder structure. We enhance the short-long term performance and interpretability with an attention and a context matcher mechanism. We perform experiments on high-scale, real-life, benchmark numerical weather dataset, ERA5 hourly data on pressure levels, and forecast the temperature. The results show significant improvements in capturing both spatial and temporal correlations with attention matrices focusing on different parts of the input series. Our model obtains the best validation and the best test score among the baseline models, including ConvLSTM forecasting network and U-Net. We provide qualitative and quantitative results and show that our model forecasts 10 time steps with 3 hour frequency with an average of 2 degrees error. Our code and the data are publicly available