55 research outputs found
Ultrasonographic features of prenatal testicular torsion: Case report
Although prenatal testicular torsion (PNTT) is rarely observed,it is an important condition that can cause bilateralvanishing testis. Generally, PNTT cases observed asextravaginal torsion and treatment is emergency surgicalop-eration. In this article, 39 week presented a case diagnosedin the prenatal testicular torsion. PNTT diagnosiswas confirmed by Doppler ultrasonography and emergencysurgery was performed. Extravaginal left testiculartorsion gangrene and necrosis of the testis was observedin the operation. Left orchiectomy was performed andintrauter-ine ultrasonographic diagnosis was found to becorrect.Key words: Testicular torsion, prenatal diagnosis, features,ultrasonograph
Investigation Of Impacts Of Aerosols On Eastern Mediterranean Region Climate
Tez (Doktora) -- İstanbul Teknik Üniversitesi, Avrasya Yer Bilimleri Enstitüsü, 2014Thesis (Ph.D.) -- İstanbul Technical University, Eurasia Institute of Earth Sciences, 2014Doğu Akdeniz Bölgesi artan nüfusu ve düşük çevresel performans göstergeleriyle çevre ve atmosfer bilimlerinde gün geçtikçe önem kazanmaktadır. Hava kirliliği, bölgedeki çevre kalitesini azaltan problemlerden biridir. Sahra tozunun uzun mesafeli taşınımı hava kirliliğine etki eden en önemli etkenlerden biridir. Bu tezin ilk bölümünde amaç, öncelikle mineral tozun partikül madde konsantrasyonları üzerindeki etkisini araştırmak, toz taşınımını modelleyerek, sonuçları uydu görüntüleri ve yer gözlemleri ile karşılaştırmak, aerosol optik değerleri belirlemek, tozun radyatif etkisini bir toz episoduyla karşılaştırmaktır. Çevre ve Şehircilik Bakanlığı'ndan İstanbul'daki 10 farklı istasyon için, 2004-2010 yılları aralığı partikül madde verisi temin edilmiştir. Saatlik olarak alınan veri, günlük ortalamaya ve sonra da aylık ortalamaya çevrilmiştir. Günlük verilerin öncelikle Avrupa Komisyonu Standardı olan 50 µg/m3'yi aşıp aşmadığı kontrol edilmiştir. İstanbul'da bahar ayında ortalama 49 gün, kış döneminde ortalama 45 gün, sonbaharda 41 gün sınırı aşmıştır. DREAM Model çıktılarına göre (Nickovic et al. 2001; Perez et al. 2006) yüksek PM10 konsantrasyonları mineral toz taşınımıyla önemli şekilde koraledir (23% kış ve 58% ilkbahar). Çalışmanın ilk kısmında RegCM4.1 modeli Sahra tozunun etkilerini ayrıntılı şekilde incelemek amacıyla kullanılmıştır. 21-24 Mart 2008 tarihleri arasındaki periyotta, günlük ortalama partikül madde konsantrasyonları Marmara Bölgesi'nde 180 µg/m3'ye ulaşmaktadır. Model sonuçları, PM10 konsantrasyonları ve uydu görüntüleriyle iyi şekilde korale çıkmıştır. RegCM4.1 Mart 2008 episodunu iyi şekilde modellemiştir ve toz taşınımını uydu görüntülerine benzer şekilde gerçekleştirdiği gözlenmiştir. Ege ve Marmara Bölgeleri'ni yoğun şekilde etkileyen 23 Mart 2008 gününde, Ege'de günlük ortalama 102 µg/m3 ve Marmara'da 117.3 µg/m3 PM10 konsantrasyonu ölçülmüştür. Ölçüm değerleri Çevre ve Şehircilik Bakanlığı'ndan elde edilmiştir. Model performansı AOD model çıktılarına ve AERONET gözlemlerine göre değerlendirilmiştir. Kontrol için Erdemli, Sivastopol ve Eilat istasyonları seçilmiştir. Gözlem ve model sonuçları korelasyon katsayısı 0.6'dır. Aynı gün model çıktılarına göre Ege Bölgesi'nde 1.11 olarak hesaplanan AOD, Marmara Bölgesi için 0.87 olarak hesaplanmıştır. Ortalama kuru çökelme sırasıyla 201.13 mg/m2 ve 96.67 mg/m2 olarak hesaplanırken, kolon derinliği 1009.9 mg/m2 ve 745.37 mg/m2 olarak hesaplanmıştır. Mineral toz taşınımı, tozun saçıcı özelliği nedeniyle ayrıca radyatif güdümlemeyi de etkilemektedir. Kısa dalga boylu radyasyon yüzeyde ve atmosferin tepesinde, Ege Bölgesi'nde 71.4 W/m2 ve 33 W/m2 azalırken, Marmara Bölgesi'nde 61.9 W/m2 ve 28.8 W/m2 azalmaktadır. Uzun dalga boylu radyasyon yüzeyde ve atmosfer tepesinde Ege Bölgesi'nde 10.7 W/m2 ve 4.4 W/m2 artarken, Marmara Bölgesi'nde and 6.9 W/m2 ve 4 W/m2 artmaktadır. Bu çalışmada Türkiye'nin batısında etkili olmuş bir episot için atmosferik özellikler ve radyatif güdümleme incelenmiştir. Bu çalışmanın ikinci aşaması, mineral tozların iklim üzerine etkisinin değerlendirilmesidir. Sahra'dan gelen mineral tozların iklim üzerine önemli etkisi bulunmaktadır. Mineral tozlar özellikle saçıcı özelliğe sahip oldukları için gelen radyasyonun bir kısmının geri yansıtılmasına ve dolayısıyla sıcaklıkların azalmasına sebep olmaktadır. Öte yandan Sahra'dan tozun taşınması meteorolojik koşullara bağlıdır. Dolayısıyla iklim değişikliği de mineral toz kaynaklarını ve taşınım yollarını etkileyebilmektedir. Bu nedenle geri besleme mekanizması çift yönlü değerlendirilmelidir. Çalışmanın ikinci aşamasının amacı, mineral tozların Akdeniz iklimi üzerine etkisinin değerlendirilmesidir. Bu etkiyi değerlendirmek için, bölgesel iklim modeli RegCM4.1 ile 10 senelik 3 ayrı dönemin (1991-2000, 2041-2050, ve 2091-2100) simülasyonu yapılmıştır. Her bir dönem ayrı ayrı toz içeren ve içermeyen durumlar için çalıştırılmıştır. Model domaini bütün Akdeniz Bölgesi'ni içermektedir. Model sınırları Sahra Çölü 25° kuzey enleminden, Kuzey Avrupa'da 50° kuzey enlemine kadar, batıda 15°, doğuda 45° boylamına kadardır. Yatayda çözünürlük 27 km x 27 km, dikeyde 18 sigma seviyesidir. Atmosfer tepesi 50 hPa'dır. Model başlangıç ve sınır koşulları ECHAM5 simülasyonları A1B senaryosu simülasyonlarından alınmıştır. A1B senaryosu bütün enerji kaynaklarının dengeli kullanıldığı bir senaryodur. Toz bütçesinin genişlemesine bir analizi için, yüzey emisyonları, kolon yükü, çökelme, aerosol optik derinlik üzerine her dönem için detaylı bir araştırma yapılmıştır. Gelecekteki iklim için ortaya konulan sonuçları referans periyotla kıyaslayınca, gelecekteki dönemde toz emisyonlarının daha güneye doğru kaydığı gözlenmiştir. Domainin güney bölümünde emisyonların 2041-2050 döneminde %15, 2091-2100 döneminde %20 arttığı görülmektedir. Bu durum yüzey rüzgarlarının genel paterninin değişmesinden kaynaklanmaktadır. Rüzgarlar aşağı enlemlerde güçlenir. Bu da özellikle Azor antisiklonlarının kuzeye doğru kayarak güçlenmesinden kaynaklanır. Bu durum toz yükünün domainin batısında %8 artmasına, Doğu Akdeniz'de %10 azalmasına sebep olmaktadır. Kolon yükü ayrıca aerosol optik derinliği ve toz radyatif güdümlemeyi de etkilemektedir. 2041-2050 döneminde Batı Akdeniz'de aerosol optik derinlik % 15 artarken, Doğu Akdeniz'de %10 azalmaktadır. 2091-2100 döneminde de benzer değişiklik görülmektedir. Tozun net radyasyon bütçesi üzerinde etkisi her 10 yıllık periyotta tozun dahil olduğu ve olmadığı durumlar için değerlendirilmiştir. Yüzeyde kısa dalga boylu net radyasyon, tozun kaynağı olan Sahra bölgesinde 20 W/m2 kadar azalırken, Güney Avrupa ve Akdeniz Bölgesi'nde 8 W/m2 kadar artmıştır. Kısa dalga boylu net radyasyon atmosferin tepesinde 3 W/m2 kadar azalmıştır. Benzer şekilde 10 yıllık dönemler için sıcaklık ve yağış değişiklikleri de incelenmiştir. Tozun her dönemde Avrupa üzerinde 0.2 Cº sıcaklık azalmasına, Afrika üzerinde 0.5 Cº sıcaklık azalmasına sebep olacağı görülmüştür. Yağışta 3 dönem için de anlamlı bir değişiklik olmamıştır.Eastern Mediterranean is a region which has increasing population growth with low Environmental Performance Indicator. Air pollution is one of the problems, which decreases the environmental quality. It is known that long-range transport of Saharan dust is one of the main contributors to the air pollution problem. The purpose of the first section of this study is to investigate the relationship between high particulate matter concentrations and mineral dust transport using regional climate modelling, satellite data as well as in-situ observations and to determine the aerosol optical properties and radiative effects of aerosols for a dust transport episode. PM10 values for the selected regions for the episode in Turkey and at 10 different stations in Istanbul for the period 2004-2010 were provided by the Turkish Ministry of Environment. Daily mean PM10 concentrations exceeding the European standard of 50 µg/m3 were found to be on average, 49 days for the Spring period, 45 days for the Winter period, and 41 days for the Fall period for Istanbul. DREAM model output suggests that high PM10 concentrations correlate highly with mineral dust transport episodes from Saharan desert (i.e., 23% for winter and 58% for spring). During the period between March 21st and 24th, 2008, observed daily mean of PM10 concentrations reach up to 180 µg/m3 in Marmara Region. Model results highly correlated with PM10 concentrations and satellite image. It is found that RegCM4.1 is able to model March 2008 episode and it can capture the dust pattern correctly in comparison with the satellite image. On March 23th 2008, when the dust episode affecting Aegean and Marmara Regions intensively, daily mean PM10 was 102.6 µg/m3 in Aegean Region and 117.3 µg/m3 in Marmara Region according to the data provided by Turkish Ministry of Environment and Urbanization. Model performance was checked through the AOD model outputs and AERONET observations. Three stations were selected which are affected stations such as Erdemli and Sevastopol and control station Eilat. Correlation coefficient was calculated around 0.6. On March 23th, AOD is 1.11 in Aegean Region and 0.87 in Marmara Region according to the RegCM4.1 model results. Mean dry deposition was 201.13 mg/m2 and 96.67 mg/m2 and column burden was 1009.9 mg/m2 and 745.37 mg/m2 respectively. Dust transport causes changes in radiative forcing because of the highly scattering feature of mineral dust. Short wave radiation at surface and at ToA decreased around 71.4 W/m2 and 33 W/m2 in Aegean Region and 61.9 W/m2 and 28.8 W/m2 in Marmara Region respectively. Long wave radiation at surface and ToA increased around 10.7 W/m2 and 4.4 W/m2 in Aegean Region and 6.9 W/m2 and 4 W/m2 in Marmara Region respectively. The first part of this study shows the atmospheric properties and radiative forcing during an important dust episode affecting west of Turkey. As a second aim of this study, climatic effect of mineral dust was evaluated. Dust from Saharan Desert is an important component of the climate of the Mediterranean basin. The emissions and transport of dust from Sahara to Europe depends on meteorological conditions, therefore climate change can affect the sources of mineral dust and its transport pathways. On the other hand dust has also an effect on climate by modifying the radiative budget in the atmosphere. The objective of this study is to identify the effect of mineral dust on the climate of Mediterranean. In order to quantify this effect, we simulated with the regional climate model RegCM-4.1 for three 10-years time periods (1991-2000, 2041-2050, and 2091-2100). The model domain covers the entire Mediterranean Sea, including the Saharan Desert between 25°N and Northern Europe at 50°N. The horizontal resolution is 27 km x 27 km with 18 vertical layers from surface to 50 hPa. The ECHAM5 simulations of scenario A1B were used to provide boundary and initial conditions to RegCM simulations. To show the effect of dust on climate, we performed 2 simulations, for each 10-year period with dust and without dust. A comprehensive analysis of the dust budget, including surface emissions, burden, deposition for present and future climate are presented in this study. Compared to present climate, a shift of mineral dust emissions towards southern latitudes of Saharan Desert was observed for the future. In the southern part of the domain dust emissions increased by 15% and 20% in 2040s and 2090s, respectively. This is due to a change in the general pattern of surface winds, which are strengthening at lower latitudes, probably due to a strengthening and relocation of the Azores anticyclone towards north in future climate conditions. This generates a change in dust burden over the Mediterranean and decreases particularly in the Eastern Mediterranean (10%) and increases in the West Mediterranean (8%). The changes in burden of dust determine also a change in the distribution of the aerosol optical depth (AOD) and the dust radiative forcing. In the 2040s AOD increased by 15% in the Western Mediterranean and decreased by 10% in the Eastern Mediterranean. Similar changes were also simulated for the end of the 21st century. The impact of dust on the net radiative budget was quantified for the single 10-years periods by comparing the simulations with dust and without dust. Shortwave net radiation at surface was decreasing up to 20 W/m2 over the source regions and 8 W/m2 over Mediterranean Sea and South Europe. Shortwave net radiation at the top of atmosphere was decreasing 3 W/m2 over the source region. Similarly we present also the changes on surface temperature and precipitation for the single 10-years periods. Dust caused an average temperature decrease of 0.2 Cº over Europe and 0.5 Cº over the African continent for the period 1991-2000. A similar impact was found for the 2041-2050 period. Smaller temperature changes simulated for the end of the 21st century. No significant changes were observed in precipitation for the 3 periods.DoktoraPh.D
MATHEMATICAL MODELING of THERMOELECTRIC GENERATOR by REGRESSION ANALYSIS
As countries grow, their need and demand for energy grow as well. The development of the technology and industry, which come to exist due to the growth of the country, a brings about a rise in energy consumption, as well as increasing the damage to the environment. Therefore, as the environmental and energy-related issues started to emerge more and more, we have seen an increase in the number of studies on energy production and its effects on the environment. Such studies highlight the renewable energy sources among the non-polluting alternative energy sources. Geothermal energy, particularly, shines out among the other renewable energy sources. It is a clean energy source that has been sustained since the Earth was formed. This study focuses on the design of a device named thermoelectric generator (TEG) that converts a renewable energy source, geothermal energy, directly into electric energy. Hence, we ran a simulation of a regression analysis and mathematical model on the thermoelectric modules TEC1-12706 and TEC1-12710, which can easily be found on the market, and then crosschecked the simulation results of different temperature, pressure, and water flow with experiments. The values for current, voltage, power, hot and cold surface temperatures, and the temperature difference between hot and cold surfaces were constantly monitored and recorded. The results of the experiment were compared using the regression analysis method. For the device TEC1-12706, error percentage of 9 experiments was 16.52% while it was 9.70% for TEC1-12710. At 90°C temperature difference, for TEC1-12706, output voltage was Vmax = 2.03V, output power Pmax = 2.17W, and efficiency 32.15%. For TEC1-12710, output voltage was Vmax = 2.11V, output power Pmax = 3.42W, and efficiency 38.53% [1,2]
OPTIMIZATION OF NICKEL EXTRACTION FROM LATERITIC ORE IN HYDROCHLORIC ACID SOLUTION WITH HYDROGEN PEROXIDE BY TAGUCHI METHOD
Taguchi optimization method was used to determine optimum conditions for the extraction of nickel from lateritic ore in hydrochloric acid solution with hydrogen peroxide. Leaching time, stirring speed, temperature, hydrochloric acid concentration and hydrogen peroxide concentration were chosen as parameters. The optimum conditions for dissolution were found as leaching time of 240 min, a temperature of 70°C, hydrochloric acid concentration of 3 M, hydrogen peroxide concentration of 0.1 M and without stirring. The experimental results under optimum leaching conditions, showed that the extraction of nickel from lateritic ore was 90.66%. Analysis of variance (ANOVA) was applied to experimental results. Percentage contributions of each factor for the extraction of nickel were determined
TOPRAKTEPE-BEYŞEHİR (KONYA) KROMİTLERİNİN YÜKSEK ALAN ŞİDDETLİ YAŞ MANYETİK AYIRMA İLE ZENGİNLEŞTİRİLMESİ
In this work, optimum enriching possibilities of Topraktepe-Beysehir (Konya) chromitesfrom abondoned mine (mined by ADO Mining Inc.) were searched. Enriching method employed. In thisresearch study was high intensity wet magnetic separation (Boxmag Rapid LHWL type). Magneticseparation tests were carried out by using 250 g samples of – 0.106+0.075 mm, -0.075+0.053 mm, -0.053+0.038 mm, -0.038 mm particle fractions. Effects of current intensity applied through magneticseparator to Cr2O3 grade and recovery for each particle size were researched in detail. In the tests,current intensity of 5, 10, 20 amperes and voltages of 40, 90, 185 volt were applied to selected fourparticle fractions. According to test results, it was observed that the best results were obtained by using20 ampere of current intensity. As a result of tests, it was showed that concentrates could be producedwith a Cr2O3 grade of 51.06 %, recovery of 86.67 %, weight of 69.37 % in -0.106+0.075 mm particlefraction, Cr2O3 grade of 51.74 %, recovery of 86.55 %, weight of 77.32 % in -0.075+0.053 mm particlefraction, Cr2O3 grade of 50.13 %, recovery of 60.14 %, weight of 57.18 % in -0.053 +0.038 mm particlefraction, Cr2O3 grade of 49.79 %, recovery of 69.74 %, weight of 39.75 % in -0.038 mm particle fractionusing 20 ampere current intensity in all tests.Bu çalışmada, ADO Madencilik A.Ş. tarafından işletilmiş ve daha sonra terkedilmiş olanTopraktepe-Beyşehir (Konya) kromitlerinin “Boxmag Rapid LHWL” tipi yüksek alan şiddetli yaşmanyetik ayırıcı ile optimum koşullarda zenginleştirilebilme olanakları araştırılmıştır. Manyetik ayırmadeneyleri, -0.106+0.075 mm, -0.075+0.053 mm, -0.053+0.038, -0.038+0.000 mm boyutlarında 250 gramlıknumuneler ile yapılmıştır. Her bir boyut için ayrı ayrı akım şiddetinin ve voltaj değerlerinin Cr2O3tenörüne ve verimine etkisi incelenmiştir. Deneylerde dört ayrı fraksiyon aralığında 5, 10, 20 amperlikakım şiddeti ve 40, 90, 185 volt değerleri test edilmiştir. Yapılan deney sonuçlarına göre, 20 amper akımşiddetinde en iyi sonuçların alındığını görülmüştür. Bu sonuçlara göre, -0.106+0.075 mm fraksiyonunda20 amper akım şiddetiyle % 69.37 ağırlık oranında, % 86.67 verim ile % 51.06 Cr2O3 tenörlü konsantre, -0.075+0.053 mm fraksiyonunda 20 amper akım şiddetiyle % 77.32 ağırlık oranında, % 86.55 verim ile %51.74 Cr2O3 tenörlü konsantre, -0.053+0.038 mm fraksiyonunda 20 amper akım şiddetiyle % 47.18 ağırlıkoranında, % 60.14 verim ile % 50.13 Cr2O3 tenörlü konsantre, -0.038 +0.000 mm fraksiyonunda 20 amperakım şiddetiyle % 39.75 ağırlık oranında, % 69.74 verim ile % 49.79 Cr2O3 tenörlü konsantre, eldeedilmiştir
The effect of vaginal bleeding and non-spesific pelvic pain on pregnancy outcomes in subchorionic hematomas cases
Objectives: To determine the clinical differences and factors affecting early pregnancy outcome in the first and early second trimester subchorionic hematoma cases.
Material and methods: This study involved with the retrospective analysis and evaluation of 81 cases diagnosed with subchorionic hematoma. The patients were grouped according to the gestational periods, symptoms at the time of admission, ratio of surrounding hematoma to the gestational sac, and whether there was a pregnancy loss. The groups were compared according to the clinical features and pregnancy outcomes.
Results: The ratio of surrounding hematoma to the gestational sac in the group with pregnancy loss was significantly higher (p = 0.002). When the cut-off value was 35.5%, it could determine the possibility of a complication in pregnancy with 70% sensitivity and 75% specificity. Nonspecific pelvic pain were significantly higher in the pregnancy loss group than in the other group. Logistic regression analysis was performed to determine the effect of these two parameters on the pregnancy outcome. Although the presence of non-specific pelvic pain is more in the group with pregnancy loss; there was no effect of on pregnancy outcome (p = 0.141). The risk of pregnancy loss increased 4.5 fold if the ratio of ScH to gestational sac was above 35% (p = 0.027).
Conclusions: In the cases of subchorionic hematoma, we concluded that when the ratio of surrounding hematoma to the gestational sac increased and when it was accompanied by nonspecific pelvic pain, the hospitalization period of the patients increased and the ratio of pregnancy loss was higher
Rudimentary horn pregnancy — ten years of experience
Objectives: This study aimed to evaluate data on early diagnosis and therapeutic management of rudimentary hornpregnancy (RHP).Material and methods: Patients diagnosed with RHP at a tertiary center between for two periods of 2008–2012 and2013–2018 were analysed retrospectively. We obtained information of patients from hospital electronic archive registrationsystem. Data on demographic characteristics, clinical presentation, gestational age at presentation, presenting symptoms,diagnostic methods, and therapeutic management were noted and analysed by descriptive statistical method. Demographicdatas, the complaint of patient’s admission to hospital, history of cesarean section, preliminary diagnosis and intraoperativediagnosis were compared between periods of 2008–2012 and 2013–2018.Results: A total of 14 RHP patients were included. Eight (57.1%) of these patients were diagnosed between 2008–2012 (Group1), whereas six patients (42.9%) were diagnosed between 2013–2018 (Group 2). Rudimentary horn was non-communicatingin 13 patients (92.8%). Communicated form was observed in 1 patient in group 1. RHP was diagnosed on the left side in ninepatients (64.2%). Six of these patients were observed in group 1 and 3 were in group 2. The pre-rupture diagnosis was madein 10 (71.4%) patients. Six (100%) of 10 patients were in group 2. In addition, in group 1, four patients (50%) experiencedintraoperative RHP rupture. RHP was diagnosed before rupture in 2 (33.3%) patients in group 2.Conclusions: It is an indication of advanced ultrasonographic technology as well as increased carefulness on the physicianside and raised alertness on the patient side that today both RHP and preoperative rupture of RHP are less frequent.Still, further awareness is required among physicians of the necessity of excision of a rudimentary horn that is detectedat the time of C-section
Factors associated with complications of vaginal hysterectomy in patients with pelvic organ prolapse — a single centre’s experience
Objectives: The study aimed to examine the predisposing factors that play a role in the development of complications in patients undergoing vaginal hysterectomy. Material and methods: This retrospective analysis was performed on data provided from 239 patients who underwent vaginal hysterectomy due to uterine prolapse at a single centre between January 2008 and August 2018. Complications were defined according to Clavien-Dindo classification of complications. The patients were divided into two groups: with and without complications. We built a model using multivariable logistic regression to examine the relationships between complications and five candidate predictors. Results: Intra/postoperative complications developed in 30 patients, and the complication rate was found to be 12.5%. 87.2% of the reported complications were classified as Grade ≤ 2 according to Clavien-Dindo system. It was found that complications were associated with factors such as intraoperative concurrent salpingo-oophorectomy [Odds ratio (OR): 1.24 (1.1–1.4)], low preoperative haemoglobin [OR: 0.96 (0.94–0.98)], uterine weight [OR: 2.69 (2.62–2.76)], and long operation time [OR: 1.04 (1.02–1.07)]. History of pelvic surgery was not found to increase complication rate [OR: 1.11 (0.96–1.27), p = 0.13]. Our multiple logistic regression model correctly classified 74% of participants within the Receiver Operating Characteristic (ROC) curve. Conclusions: Preoperative anaemia, large uterus and concomitant adnexectomy were found to be factors associated with complications during and after vaginal hysterectomy for pelvic organ prolapse
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