Frequency and voltage partitioning in presence of renewable energy resources for power system (example: North Chile power network)

This paper investigates techniques for frequency and voltage partitioning of power network based on the graph-theory. These methods divide the power system into distinguished regions to avoid the spread of disturbances and to minimize the interaction between these regions for frequency and voltage control of power system. In case of required active and reactive power for improving the performance of the power system, control can be performed regionally instead of a centralized controller. In this paper, renewable energy sources are connected to the power network to verify the effect of these sources on the power systems partitioning and performance. The number of regions is found based on the frequency sensitivity for frequency partitioning and bus voltage for voltage partitioning to disturbances being applied to loads in each region. The methodology is applied to the north part of Chile power network. The results show the performance and ability of graph frequency and voltage partitioning algorithm to divide large scale power systems to smaller regions for applying decentralized controllers.Peer ReviewedPostprint (published version

The Effect of Electronic Flashcards on EFL Students' Vocabulary Learning: The Case of Saudi Arabia

This study aimed to investigate the effect of electronic flashcards on EFL vocabulary learning of preparatory-year female students at a  Saudi Arabia. It was conducted following the quantitative research methodology with a quasi-experimental design. Two groups were assigned: an experimental group who used electronic flashcards, and a control group who employed the traditional method of vocabulary learning. A pre-test and a post-test were administered in order to appraise their performance before and after the experiment. The results revealed that the post-test scores of students in the experimental group were significantly higher than their pre-test. Also, the results showed that electronic flashcards promoted students' vocabulary, causing a statistical significance in comparison to the control group. Based on these findings, this study was able to draw a number of implications and recommendation

Jaringan WBN Multisensor untuk Aplikasi Monitoring Kesehatan Pasien

-Aktifitas riset terkait penggunaan sistem jaringan sensor nirkabel untuk monitoring kesehatan manusia terus mengalami perkembangan yang pesat beberapa tahun terakhir ini. Penelitian terdahulu di Jurusan Teknik Elektro UNHAS, Makassar dalam bidang ini telah menghasilkan prototipe jaringan sensor nirkabel untuk monitoring denyut nadi. Aplikasi ini menggunakan sensor tunggal denyut nadi manusia dengan memanfaatkan jaringan Xbee-Pro sebagai media transfer data antara sistem WBN (wireless body network) manusia dan komputer sebagai penerima serta penampil grafik sinyal medik. Untuk kegiatan riset yang dikembangkan saat ini sistem WBN menggunakan lebih dari satu sensor (multisensor), yakni sensor detak nadi dan sensor suhu LM-35 dengan memanfaatkan jaringan nirkabel yang berbeda (bluetooth) agar dapat ditampilkan pada smartphone berbasis android. Cara kerja sistem ini adalah dengan mengambil data pendeteksi pulse sensor dan sensor suhu kemudian data dikirim oleh piranti modul arduino melalui perangkat bluetooth untuk ditampilkan pada aplikasi Bluetooth SPP Pro smartphone android

Pemilihan Model Regresi Polinomial Lokal Dan Spline Untuk Analisis Data Inflasi Di Jawa Tengah

Inflation becomes one of important problems as parameter of economic growth and determiner factor for government in formulating fiscal, monetary and nonmonetary policy. But, these days the policies were arranged can't give the positive response to inflation pressure in the future. Therefore, the prediction of inflation rates are needed. Inflation rates are predicted by nonparametric regression approach because of the fluctuation of inflation which can't be solved by classic time series models. In this research, the best nonparametric regression models are selected between local polynomial and spline regression to predict Central Java Inflation movement in 2014. Based on analysis, the best nonparametric regression is spline order 2, knot points are 5,37; 5,44; 5,59 and 9,01 with GCV 0,4367286. By using that model, the prediction of Central Java inflation got down since October 2013 until February 2014 on level 7% and March until December 2014 on level 6%

Sistem Jaringan Nirkabel Dual-Sensor untuk Monitoring Data Medik Pasien

Riset tentang penggunaan sistem jaringan nirkabel untuk monitoring tanda-tanda vital kesehatan manusia terus mengalami perkembangan. Salah satu penelitian sebelumnya menghasilkan aplikasi jaringan sensor nirkabel untuk monitoring denyut nadi. Aplikasi yang dihasilkan berupa penggunaan jaringan nirkabel untuk memantau denyut nadi manusia, aplikasi ini menggunakan sensor tunggal (single sensor) dengan menggunakan jaringan Xbee sebagai media pengirim data. Dari uraian tersebut, dibutuhkan penelitian lanjutan dengan orientasi riset pada pemakaian lebih dari satu sensor (dual-sensor) serta penggunaan jaringan nirkabel yang berbeda yaitu jaringan bluetooth untuk mengirim data dari perangkat sensor ke smartphone android sebagai perangkat penerima. Hasil pengujian throughput dan data loss menunjukkan\ud bahwa bluetooth mempunyai stabilitas yang baik dalam melakukan pengiriman data tanpa data loss dalam jangkauan maksimal 9,5 meter dalam ruang terbuka dengan\ud throughput 0,97 kbps dan maksimal 17 meter dalam ruang tertutup dengan throughput yang sama yaitu 0,97 kbps

Effectiveness of high dose spinal cord stimulation for non-surgical intractable lumbar radiculopathy

OBJECTIVES: Spinal cord stimulation (SCS) is being increasingly used in non-surgical intractable low back pain. This study was designed to evaluate the efficacy of high-dose (HD) SCS utilizing sub-perception stimulation with higher frequency and pulse width in non-surgical predominant low-back pain population at 12 months. MATERIALS AND METHODS: A total of 20 patients were recruited (280 screened between March 2017 and July 2018) to undergo percutaneous fluoroscopic-guided SCS (Medtronic 8 contact standard leads and RestoreR IPG), with T8 and T9 midline anatomical parallel placement. Sixteen patients completed 12 months follow-up (500 Hz frequency, 500 μs pulse width, and 25% pulse density). Differences in patients’ clinical outcome (NRS back, NRS leg, ODI, PGIC, and PSQ) and medication usage (MQS) at 1, 3, and 12 months from the baseline were assessed using non-parametric Wilcoxon paired test. RESULTS: The mean NRS scores for back pain (baseline 7.53) improved significantly at 1, 3, and 12 months; 2.78 (p < 0.001), 4.45 (p = 0.002), and 3.85 (p = 0.002), respectively. The mean NRS score for leg pain (baseline 6.09) improved significantly at 1 and 3 months; 1.86 (p < 0.001) and 3.13 (p = 0.010), respectively. Mean NRS for leg pain at 12 months was 3.85 (p = 0.057). ODI and sleep demonstrated significant improvement as there was consistent improvement in medication particularly opioid usage (MQS) at 12 months. CONCLUSIONS: This study demonstrates that anatomical placement of leads with sub-perception HD stimulation could provide effective pain relief in patients who are not candidates for spinal surgery

Measurement of Wall Shear Stress Exerted by Flowing Blood in the Human Carotid Artery: Ultrasound Doppler Velocimetry and Echo Particle Image Velocimetry

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordVascular endothelial cells lining the arteries are sensitive to wall shear stress (WSS) exerted by flowing blood. An important component of the pathophysiology of vascular diseases, WSS is commonly estimated by centerline ultrasound Doppler velocimetry (UDV). However, the accuracy of this method is uncertain. We have previously validated the use of a novel, ultrasound-based, particle image velocimetry technique (echo PIV) to compute 2-D velocity vector fields, which can easily be converted into WSS data. We compared WSS data derived from UDV and echo PIV in the common carotid artery of 27 healthy participants. Compared with echo PIV, time-averaged WSS was lower using UDV (28 ± 35%). Echo PIV revealed that this was due to considerable spatiotemporal variation in the flow velocity profile, contrary to the assumption that flow is steady and the velocity profile is parabolic throughout the cardiac cycle. The largest WSS underestimation by UDV was found during peak systole (118 ± 16%) and the smallest during mid-diastole (4.3± 46%). The UDV method underestimated WSS for the accelerating and decelerating systolic measurements (68 ± 30% and 24 ± 51%), whereas WSS was overestimated for end-diastolic measurements (−44 ± 55%). Our data indicate that UDV estimates of WSS provided limited and largely inaccurate information about WSS and that the complex spatiotemporal flow patterns do not fit well with traditional assumptions about blood flow in arteries. Echo PIV-derived WSS provides detailed information about this important but poorly understood stimulus that influences vascular endothelial pathophysiology.National Institute of HealthNational Institute for Health Research (NIHR

False Beliefs About Diabetes Mellitus in the Kurdistan Region of Iraq: A Population-Based Study

Background. Diabetes mellitus (DM) is a chronic, non-transmissible health condition distinguished by high blood glucose levels caused by faulty insulin secretion and impaired insulin activity. People play an essential role in preventing and managing their illnesses. Thus, the misconceptions may negatively influence the prevention and management of DM. The aim of this study was to gauge the extent of knowledge among the general population concerning DM, to determine the prevalence of misconceptions about DM in the community, and to find the factors influencing them. Methods. A population-based study was conducted in Duhok Province, the Kurdistan Region of Iraq. A total of 2,305 adults were enrolled in the study. The study data were collected by face-to-face interview. The survey questionnaire comprised two sections: the first section included basic demographic characteristics of participants, while the second section consisted of ten questions to identify common misconceptions about DM among participants. Results. Among the participants, there were 1,406 (61.0%) females. Participants’ age ranged from 18 to 90 years (the mean age: 54 ± 13.69 years). The most common misconceptions positively responded to were “Will I become addicted to insulin if I start taking it?”, followed by“ Does DM occur because of increased sugar intake?”. Male gender was associated with higher level of misconceptions. In addition, the misconceptions were more prevalent among diabetics as they might seek treatment from non-professionals. There was a significant association between education status and the prevalence of misconceptions. Healthcare workers were found to have a better knowledge about DM compared to the general population. Surprisingly, certain myths were prevalent even among healthcare workers. Conclusions. Certain myths and misconceptions have been pervasive in our society. Actions must be taken to dispel these misconceptions as they lead to an avoidable burden of disease. Therefore, people’s knowledge of DM needs to be enhanced through educational programs, social media, television, newspapers and campaigns

Organic carbon sequestration and storage in vegetated coastal habitats along the western coast of the Arabian Gulf

Certain coastal ecosystems such as mangrove, saltmarsh and seagrass habitats have been identified as significant natural carbon sinks, through the sequestration and storage of carbon in their biomass and sediments, collectively known as \u27blue carbon\u27 ecosystems. These ecosystems can often thrive in extreme environments where terrestrial systems otherwise survive at the limit of their existence, such as in arid and desert regions of the globe. To further our understanding of the capability of blue carbon ecosystems to sequester and store carbon in such extreme climates, we measured carbon sediment stocks in 25 sites along the Western Arabian Gulf coast. While seagrass meadows and saltmarsh habitats were widely distributed along the coast, mangrove stands were much reduced as a result of anthropogenic pressures, with 90% of stands having been lost over the last century. Carbon stocks in 1 m deep surface sediments were similar across all three blue carbon habitats, with comparable stocks for saltmarsh (81 ± 22 Mg Corg ha−1), seagrass (76 ± 20 Mg Corg ha−1) and mangroves (76 ± 23 Mg Corg ha−1). We recorded a 38% decrease in carbon stocks between mature established mangrove stands (91 Mg Corg ha−1) and recently planted mangroves (56 Mg Corg ha−1). Mangroves also had the lowest carbon stock per total area owing to their very limited spatial coverage along the coast. The largest stock per total area belonged to seagrass beds as a result of their large spatial coverage within the Gulf. We employed 210Pb dating to determine the sediment accretion rates in each ecosystem and found mangrove habitats to be the most efficient carbon sequesters over the past century, with the highest carbon burial rate of the three ecosystems (19 g Corg m−2 yr−1), followed by seagrass (9 g Corg m−2 yr−1) and saltmarshes (8 g Corg m−2 yr−1). In this work, we describe a comprehensive comparison of sediment stocks in different blue carbon ecosystems within a single marine environment and across a large geographical area, and discuss our results in a global context for other blue carbon ecosystems in the dry tropics

Fibra efetiva para vacas em lactação.

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