57 research outputs found

    Yüksek Frekans DA/DA Senkron Yükselten Dönüştürücü Tasarımı

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    Günümüz teknolojilerindeki hızlı gelişmeler, endüstriyel veya bireysel tüketicilerin mobil cihazlara olan ilgisini arttırmakta ve buna bağlı olarak Doğru Akım (DA) kullanımı da yaygınlaşmaktadır. DA kullanımına olan talebin büyümesi temel yarı iletken güç dönüştürücülerinden biri olan DA-DA dönüştürücülerin önemini de arttırmaktadır. Bu çalışmada yüksek frekanslı (280kHz) darbe genişlik modülasyon kontrollü (PWM) DA-DA senkron yükselten dönüştürücü tasarımı ve uygulaması gerçekleştirilmektedir. Tasarım ve uygulama aşamasında yüksek frekans ile çalışmanın meydana getirmiş olduğu problemler, kontrol katı ve güç katı olmak üzere ayrı ayrı değerlendirilerek, iyileştirme yöntemleri yarı iletken elemanlar ve baskı devre yapısı üzerinde uygulanarak deneysel olarak gözlemlenmiştir

    Holocene activity of Kütahya fault zone

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    Batı Anadolu Açılma Bölgesi’nin kuzeydoğu sınırında bulunan Kütahya Havzası BKB-DGD doğrultusunda uzanan bir çöküntü alanıdır ve güney kenarı belirgin bir morfoloji ile Kütahya Fay Zonu tarafından sınırlanmaktadır. Kütahya Fay Zonu boyunca jeolojik, jeomorfolojik ve jeofizik verilerden yararlanılarak yapılan çalışmalar sonucunda bu zonun, kuzey bloğun düştüğü normal fay geometrisine sahip 5 ayrı uzanımdan oluştuğu ve K50-70B doğrultusunda yaklaşık 22 km uzunluğa sahip olduğu ortaya konulmuştur. Paleosismolojik ve arkeosismolojik çalışmalar ise bu uzanım boyunca son 8000 yıl içinde yüzey kırığı oluşturan en az iki depremin meydana geldiğini ortaya koymaktadır. Bu depremlerden ilki M.Ö. 6000’li yıllarda, sonuncusu ise M.Ö. 1800’lü yıllarda Seyitömer Höyüğü’nde hasar oluşturan ve höyüğün terk edilmesine neden olan depremdir. Dolayısıyla, bu çalışmalar Kütahya Havzası’nın güneyini sınırlayan Kütahya Fay Zonu’nun Holosen’de tekrarlanan yıkıcı depremler ürettiğini ve geometrisi gözönünde bulundurulduğunda gelecekte de en az 6.5 büyüklüğünde deprem üretme potansiyeli bulunduğunu ortaya koymaktadır.Kütahya Basin which is located near the northeast boundary of the Western Anatolia Extension Region is a depression area that extends in WNW-ESE direction. Southern margin of the basin is bounded by a distinct fault morphology called Kütahya Fault Zone. Geological, geomorphological and geophysical studies on the Kütahya Fault Zone show that this zone consists of 5 different fault branches. Total length of the mapped fault zone is about 22 km in N50-70W direction. Paleoseismological and archeoseismological studies show that there are at least two surface rupturing earthquakes during the last 8000 years. First earthquake was occurred around 6000 BC and the last one was around 1800 B.C. after which the Seyitömer Tell was abandoned. Thus, this study indicates that the Kütahya Fault Zone has produced destructive earthquakes during Holocene and considering the length of the fault zone, it is possible to suggest that the fault zone has earthquake potential at least 6.5 magnitude.Publisher's Versio

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

    Surface rupture history and 18-ka-long slip rate along the Pazarcık segment of the East Anatolian Fault

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    Table and figures detailing radiocarbon ages (Table S1) and trench sites (Figures S1, S2, S3 and S3)

    Surface rupture history and 18-ka-long slip rate along the Pazarcık segment of the East Anatolian Fault

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    Table and figures detailing radiocarbon ages (Table S1) and trench sites (Figures S1, S2, S3 and S3)

    Lacustrine clay mineral assemblages as a proxy for land-use and climate changes over the last 4 kyr: The Amik Lake

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    Lake sediments are sensitive to landscape changes and most of these changes seem to be modulated by land-use (anthropogenic factors) coupled to palaeoenvironmental/palaeoclimatic changes. In its detrital fraction, the lacustrine sediments record the history of soil erosion within its catchment via the inputs of clays and others detrital products. Within a Mediterranean context, the study investigates the upper sediments infilling the central part of the Amik basin in southern Turkey. This tectonic basin was occupied and exploited by modern human at least since 6000-7000 BC. We focus on the clay mineralogy (x-ray diffraction on oriented aggregates) and magnetic susceptibility measurements (Bartington) of the sedimentary record in the area over the last 4000 years, to assess environmental changes in relation with the different land uses and/or weathering during the successive Bronze, Iron, Roman, Islamic/Ottoman and Modern civilizations. The clay fraction of Amik Lake sediments comprises smectite, kaolinite, illite, chlorite and chlorite/smectite mixed layers that are the inherited clay phases. A relative change in abundance and crystallinity and chemistry of illite attests that environmental conditions evolved in the Amik Plain from the Bronze to Modern Age in relation with climates and/or land-use changes. The history of the Amik Lake reveals different soil erosion episode. The most intense erosion phase occurred during the Bronze/Iron Ages as indicated by the clay and magnetic susceptibility proxies. The Roman period was an exceptional period with soil erosion products arriving from the watershed, probably due the water channelization. A reduction of soil erosion occurred during the post Roman period until nowadays. Significant pedogenesis transformations are evidenced, especially during the Islamic/Ottoman periods suggesting intense chemical weathering conditions related to climate change

    Characterization of building materials from the aqueduct of Antioch-on-the-Orontes (Turkey)

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    The Roman aqueduct of Antioch-on-the-Orontes (Turkey), a city located near the junction between the active Dead Sea fault and the East Anatolian fault, has been damaged several times due to historical earthquakes, as mentioned in ancient texts. The traces of repairs are studied in order to identify their potential seismic origin. The deformations of the structure were characterised thanks to a LIDAR scan. Several bricks were sampled on different parts of the city’s aqueducts, on the original structure and on repaired parts. The bricks were characterized through a petrological approach. 14C and archaeomagnetism were tested on the bricks in order to constrain the age of their production. The synthesis of all the data showed a local origin for the bricks, and led to the identification of several manufacturing techniques and several types of production, thus, confirming the potentiality of this approach to date and characterise post-seismic repairs.Archeosismicity along the Dead Sea Fault recorded by the Antioche-sur-Orontes aqueduc
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