Weld root instabilities in fiber laser welding

Powell, John,Ilar, Torbjö,rn,Frostevarg, Jan,Torkamany, Mohammad J.,Na, Suck-Joo,Petring, Dirk,Zhang, Linjie,Kaplan, Alexander F. H. Laser Institute of America 2015 Journal of laser applications Vol.27 No.supple2

Satisfaction of European Tourists – Benchmarking of EU Countries

Petr Š,tumpf,Viktor Vojtko,Barbora Valtrová People&Global Business Association 2018 Global Business and Finance Review Vol.23 No.1

High level of satisfaction of tourists is one of the most common goals of sustainable tourism destinations. The general assumption is that higher level of tourists satisfaction leads to a higher tourists loyalty to destinations. This research looks on this relationship from macro level of European Union (EU) countries. We have used data from Eurobarometer – Preferences of Europeans towards Tourism between 2013 and 2016 – to statistically compare and analyse several satisfaction indicators of European tourists incoming the chosen EU countries. The results show significant differences amongst countries as destinations and could be used to identify strengths and weaknesses of EU countries as tourism destinations. The robust data set enables the benchmarking of EU countries as tourism destinations from the tourists satisfaction point of view. This study shows the ranking of the EU countries in several dimensions of tourists satisfaction.

Impact of altered environment and early postnatal methamphetamine exposure on serotonin levels in the rat hippocampus during adolescence

Barbora Čechová,Jana Jurčovičová,Ivana Petríková,Šimon Vaculín,Štěpán Šandera,Romana Šlamberová 한국실험동물학회 2024 Laboratory Animal Research Vol.40 No.1

Background: Methamphetamine (MA) is a highly abused psychostimulant across all age groups including pregnant women. Because developing brain is vulnerable by the action of drugs, or other noxious stimuli, the aim of our study was to examine the effect of early postnatal administration of MA alone or in combination with enriched environment (EE) and/or stress of separate housing, on the levels of serotonin (5HT) in the hippocampus of male rat pups at three stages of adolescence (postnatal day (PND) 28, 35 and 45). MA (5 mg/kg/ml) was administered subcutaneously (sc) to pups (direct administration), or via mothers' milk between PND1 and PND12 (indirect administration). Controls were exposed saline (SA). Pups were exposed to EE and/or to separation from the weaning till the end of the experiment. Results: On PND 28, in sc-treated series, EE significantly increased the muted 5HT in SA pups after separation and restored the pronounced inhibition of 5HT by MA. No beneficial effect of EE was present in pups exposed to combination of MA and separation. 5HT development declined over time; EE, MA and separation had different effects on 5HT relative to adolescence stage. Conclusions: Present study shows that MA along with environment or housing affect 5HT levels, depending on both the age and the method of application (direct or indirect). These findings extend the knowledge on the effects of MA alone and in combination with different housing conditions on the developing brain and highlight the increased sensitivity to MA during the first few months after birth.

Predictors of school adjustment in high school students of immigrant origin in Western Catalonia

Hinostroza Castillo Ursula,Lapresta-Rey Cecilio,Petreñas Cristina,Janés Junit 한국다문화교육학회 2023 Multicultural Education Review Vol.15 No.3

This study explores factors influencing school adjustment in immigrant students in Catalonia, Spain. Low school adjustment levels can lead to failure or dropout, particularly among immigrant students. The research analyzes acculturation strategies, intergroup contact, perceived discrimination, and origin's impact on school adjustment. Students from African, Latin American, and European backgrounds completed a questionnaire, revealing four acculturation strategies: marginalization, assimilation to Catalan culture, integration, and assimilation to Catalan and Spanish cultures. A kmeans cluster analysis identified these patterns. Linear regression highlighted intergroup contact, integration vs. marginalization, and integration vs. assimilation to Catalan culture as significant predictors. Higher intergroup contact scores correlated with improved school adjustment, while adopting integration or assimilation to Catalan culture predicted better adjustment compared to marginalization. Understanding and addressing these factors is vital for enhancing immigrant students' educational experiences and reducing the risk of academic challenges.

Application of Acoustical Method to Characterize Nonwoven Material

Tao Yang,Xiaoman Xiong,Yuanfeng Wang,Rajesh Mishra,Michal Petrů,Jiří Militký 한국섬유공학회 2021 Fibers and polymers Vol.22 No.3

Some structural parameters, such as tortuosity, viscous and thermal characteristic lengths, are difficult to obtainthrough direct measurements. Existing indirect methods, i.e. acoustical method, make it possible to estimate theseparameters. This paper presents an application of acoustical inversion methods for estimating structural parameters ofpolyester nonwoven materials. A four-microphone impedance tube was used to measure sound reflection and transmissioncoefficients. The inversion methods used in this research are least square and Bayesian approaches. The least square methodwas achieved via Nelder-Mead algorithm. The Bayesian inversion process was conducted with Metropolis-Hastingsalgorithm and maximum a posteriori. Inversed parameters from two methods as well as front and back sides of nonwovenfabric were compared. Moreover, inversed porosity and airflow resistivity were compared with measured values. The resultsshow that the least square and Bayesian methods has a good agreement. Estimated parameters from Bayesian method wereselected for further analysis. A sizable differences on thermal characteristic length were found by comparing the values fromtwo sides, while the differences are relatively small for other parameters. It is also found that the inversed porosity, tortuosityare reasonable. The results suggest that the acoustical inversion methods can be used to accurately characterize polyesterfibrous materials.

Using ILS Mathematical Model and Measurements for Detailed Evaluating Results of Thermal Response Tests

Petr Vojcinak,Radovan Hajovsky,Jiri Koziorek 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10

Robust Control of Permanent Magnet Synchronous Motor

Petr Blaha,Pavel Vaclavek 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10

The aim of this paper is to present design of robust current controller, its validation in the environment of Matlab Simulink and its verification on a real motor using rapid prototyping system dSpace 1103. The worst case scenario in current generating part of permanent magnet synchronous motor is considered for controller synthesis. The current controller is designed using μ synthesis so as to reach defined degree of robust performance for defined variations of motor parameters. The controller design takes into account time delays caused with discretization and with finite computational time of the control algorithm. The designed controller was checked if it meets proposed requirements in the whole speed operating range. Paper also shows dependency of controller reduced order on sensitivity function template from the perspective of reached control performance.

Nation-building in post-Soviet Russia: What kind of nationalism is produced by the Kremlin?

Petr Panov 한양대학교 아태지역연구센터 2010 Journal of Eurasian Studies Vol.1 No.2

After collapse and subsequent dissolution of the Soviet Union, post-Soviet Russia faced typical problems of state-building and nation-building. Nations are assumed as political communities of Modernity. They are constructed in the process of nation-building and are based on nationalism, defined as worldview which perceives social reality through the prism of dividing the world into nations-states. Nation-building is a discursive process where state’s activities predefine the type of nationalism being rooted. Using as a starting point ‘civic versus ethnic nationalism’ dichotomy, the article develops a transformed version of this typology, which is based on two dimensions: model of national membership (openness/closeness) and model of interaction among members (universalism/hierarchical particularism). The analysis of Annual Addresses of the Russian Presidents demonstrates that the Kremlin certainly produces open model of national membership. The key feature of ‘Russianness’ in the Kremlin discourse is commitment to the Russian culture where anyone can be recognized as ‘Russian’ as long as he/she shares the Russian cultural values. At the same time, the openness is combined with neglect of ‘civicism’. In contrast to ‘civicism’, which is based on rational notions of equal rights and responsibilities and universalistic patterns of behavior, the Kremlin image of Russian nation focuses on rather sacral idea of ‘the Russian way’, great historical mission as the destination of Russia. Openness of nationalism entails permanent expansion of the nation ‘outside itself’ in order to ‘absorb’ those groups who are able to accept Russian culture. Since the acceptance requires definite period of time, at any point of time Russian nation includes both ‘core of the nation’ and ‘aspirants’ that are in hierarchical order. Consequently, from the point of the second dimension, Russian nationalism falls into the category of hierarchical particularism.

한국산 진딧물 기생봉( 벌목, 고치벌과, 진디벌아과)의 기주 정리

Petr Star 한국응용곤충학회 2000 Insecta Koreana Vol.17 No.1

진딧물에 기생하는 한국산 진디벌에 관해서 국내외의 문헌기록을 중심으로 정리하여 10종의 학명은 잘못 사용되고 있음을 확인하였으며, 재정리한 결과 한국곤충명집에서 41종이었던 진디벌은 총 62종으로 확인되었다. 이들을 속과 종에 따라 알파벳 순으로 정리한 뒤, 각 종에 대해 기주 진딧물을 명시하였고 가능한 경우 기주가 채집된 식물도 정리하였으며, 기주 진딧물별로 기생하는 진디벌을 배열하였다. As a first step toward a more comprehensive research on the taxonomy of Korean aphidiine species which are parasitic on the aphids, all the available records on their hosts and collecting data were reviewed. A list of 62 species is arranged according to the generic and then specific names alphabetically with hosts records and the host-parasitoid relationships were presented.

Microstructure Control of Grain-oriented Barium-titanate Ceramics and Their Piezoelectric Properties

Petr Pulpan,Rintaro Mori,Hiroshi Hayashi,Yoshitaka Nagamori,Yuichi Yamamoto,Satoshi Wada 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.41

A templated grain growth (TGG) method was used for the preparation of grain-oriented bariumtitanate (BaTiO3, BT) ceramics. [110]-oriented BT plate-like template particles were dispersed in a matrix of hydrothermal BT spherical particles of various sizes. The Lotgering method using the Xray diffraction (XRD) pattern determined the degree of orientation along the [110] direction (F110). An optimization of the preparation conditions was performed in terms of the template-to-matrix weight ratio (T/M), the Ba/Ti ratio, and the sintering temperature and time in order to achieve a high F110 along with a small grain size and a high density. A grain size as small as 10 µm could be reached for Ba/Ti ratios close to the stoichiometric value. Lower values led to an increase in F110 and in the grain size. A T/M bigger than 80% was necessary for F110 to be above 80% and for the grain size lower than 40 µm. The density was almost independent of the T/M and the Ba/Ti ratios. The grain growth was limited by a two-step sintering process. Small grain size, high F110 and high density are essential if the piezoelectric constant d33 is to be increased above the values for standard BT ceramics.