External lightning protection system for wind turbine blades - power performance

Previous studies conducted by the authors on the aerodynamic performance of turbine blades have shown unfavourable effects of externally mounted lightning down conductors. Owing to this, one could ask whether or not externally mounted lightning down conductors could linearly affect the power performance of the whole wind turbine as well. Therefore, this paper presents a study of the power performance of one wind turbine with an externally mounted lightning down conductor. An untwisted blade profile of NACA 4418 with and without external conductor was used on the full wind turbine model. Numerical simulations were carried out on turbine power output derived from Blade Element Momentum (BEM) theory. The results are compared and discussed. The preliminary results indicate that degradation in power performance may not be significant

Pengaruh Model Pembelajaran Berbasis Masalah Terhadap Hasil Belajar Fisika Siswa Kelas X Sman 2 Praya Tahun Pelajaran 2015/2016

– The purpose of this study was to investigate the influence of problem based learning model toward physics learning outcomes at SMAN 2 Praya grade X at the academic year 2015/2016. This study was experiment with post-test only control group design. The population of this study were all students of Xth grade with number of students were 400 students. Cluster random sampling was used to choose the class sample with X-4 as experiment class and X-6 as control class. The instrument of this study used multiple choise test with 5 alternative answer. Based from the result, data were analyzed using t-test polled varians. The data obtained 3.42 for the t-hint and 1.99 for the t-table with significant level 5%. Therefore t-hint > t-table, the H0 rejected and Ha be accepted. This result shows that problem based learning model is influencing the stuent's physics academy result at SMAN 2 Praya Xth grade academic year 2015/2016

Fallout radionuclides as indicators of soil degradation and potential loss of agricultural production in Latin American and Caribbean countries

Land degradation affects about 300 million ha of land in the Latin American and Caribbean region: 51% of this is agricultural land (180 million hectares). The ARCAL Regional Strategy Profile identifies the deficient use of agricultural soil and the resulting permanent loss of productive agricultural areas as one of the most important environmental and alimentary problems in the Latin American and Caribbean continental areas (Alimentary Security, A3, PER-ARCAL, 2007-2013). In recent times, extensive natural areas have been dramatically diminished by various human interventions. In this continental context, regional or national difficulties normally present specific characteristics and relevancies and distinct intervention needs. Indicators of the present soil conservation status are essential for an assessment of national economic impact and an evaluation of social consequences.Fil: Lohaiza, Flavia Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis ; ArgentinaFil: Juri Ayub, J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis ; ArgentinaFil: Velasco, H.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis ; ArgentinaFil: Dercon, G.. International Atomic Energy Agency. Department of Nuclear Sciences and Applications. Soil and Water Management & Crop Nutrition Subprogramme; Austri

Bloom-epistemic and sentiment analysis hierarchical classification in course discussion forums

Online discussion forums are widely used for active textual interaction between lecturers and students, and to see how the students have progressed in a learning process. The objective of this study is to compare appropriate machine-learning models to assess sentiments and Bloom\'s epistemic taxonomy based on textual comments in educational discussion forums. Our proposed method is called the hierarchical approach of Bloom-Epistemic and Sentiment Analysis (BE-Sent). The research methodology consists of three main steps. The first step is the data collection from the internal discussion forum and YouTube comments of a Web Programming channel. The next step is text preprocessing to annotate the text and clear unimportant words. Furthermore, with the text dataset that has been successfully cleaned, sentiment analysis and epistemic categorization will be done in each sentence of the text. Sentiment analysis is divided into three categories: positive, negative, and neutral. Bloom\'s epistemic is divided into six categories: remembering, understanding, applying, analyzing, evaluating, and creating. This research has succeeded in producing a course learning subsystem that assesses opinions based on text reviews of discussion forums according to the category of sentiment and epistemic analysis.Comment: 11 pages, 7 figure

Wilson\u27s disease: experience at a tertiary care hospital.

Wilson\u27s disease (WD) is a rare autosomal recessive disorder of copper metabolism. Data regarding WD is not available from Pakistan. A cross-sectional study was conducted at The Aga Khan University Hospital, Karachi, and all patients admitted with primary and secondary diagnosis of Wilson\u27s disease were added. A total of 47 patients were seen; 68% (n = 32) were male. The mean age was 26.6 ± 9.97 years. Most of the patients presented with hepatic, (n = 22, 46.8%), neurological, (n = 17, 36.2%) and psychiatric (n = 8, 17%) symptoms. Mean ceruloplasmin level was 0.17 ± 0.13 g/dl; it was \u3c 0.25 g/dl in 39 (86.6%) patients. Serum copper (Cu) was reduced in 32 (68.1%) patients and 24-hr-urinary Cu was raised in 22 (47.6%) patients. Slit lamp examination for Kayser-Fleischer (KF) rings was done on 15 (31.9%) patients and 9 (60%) of them had KF rings. Mean serum aspartate transaminase (AST) / alanine transaminases (ALT) ratio was 1.92 and median alkaline phosphatase / total bilirubin ratio was 79.30 (IQR 35.05; 166.50)

Security, usability, and biometric authentication scheme for electronic voting using multiple keys

We propose electronic voting authentication scheme, which is a key management mechanism for electronic voting system intended to limit the number of attacks on a polling station and strengthen the security control. The motivation is to diversify security requirements of messages exchanged between polling stations. There are different types of messages exchanged between polling stations and each type of message has different security needs. A security mechanism developed on the basis of a single key is not enough to ensure the diverse security needs of voting network. In electronic voting authentication scheme, every polling station is responsible to support three different types of keys. These are global key, pairwise key, and individual key. The global keys are public keys shared with all polling stations in the voting network. The pairwise key can be used for communication with polling stations. Individual keys will be used for communication with the server. To ensure authentication of local broadcast, electronic voting authentication scheme uses one-way key chains in a well-organized way. The support of source authentication is a visible advantage of this scheme. We examine the authentication of electronic voting authentication scheme on numerous attack models. The measurement demonstrates that electronic voting authentication scheme is very operative in protecting against numerous elegant attacks such as wormhole attack, Sybil attack, and HELLO Flood attack. The proposed system is evaluated and the results demonstrate that the proposed system is practical and secure as compared to the direct recording electronic and manual systems

Tuberculosis of the Gallbladder

Analysis of 5 patients with gallbladder tuberculosis who had open cholecystectomy and review of literature have shown that, although still rare it presents as a part of systemic miliary tuberculosis, abdominal tuberculosis, isolated gallbladder tuberculosis and as acalculus cholecystitis in anergic patients. There are no pathognomonic signs, the diagnosis depends on suspicion of tuberculosis, peroperative findings and histological examination