Sonlu Viskoplastisite Üzerine Düşünceler

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2008Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2008Sonlu Plastisite Teorisinde serbest enerji yoğunluğu genellikle iki parçalı olarak tanımlanmakta olup birinci kısım, deforme olmuş maddesel noktada depolanmış olan elastik enerji yoğunluğunu,ikinci kısım da dislokasyonlarda bloke edilmiş olan plastik enerji yoğunluğunu temsil etmektedir. İkinci kısım yalnızca saklı (dahili) değişkenlerin , birinci kısım ise gözlenebilen değişkenlerin fonksiyonu olarak ifade edilmektedir. Daha sonra serbest enerjinin maddesel türevi uygun tarzda hesaplanarak Calusius-Duhem eşitsizliğine yerleştirilip bilinen matematiksel işlemler yapılmaktadır. Bu çalışmada ise ,serbest enerji yoğunluğu fonksiyonu ayrıştırılmadan kullanılmakta ve aynen sürekli-ortam yaklaşımındaki format izlenmektedir.Ancak plastik deformasyon etkileri ,daha sonra bahsedeceğimiz Lee ayrışımıyla işlemlere dahil edilmekte, viskozite etkisi ise Kelvin-Voigt benzeşimi ile toplam deformasyon tansörünün maddesel türevi şeklinde ithal edilmektedir.Ayrıca genel formülasyon, gerilme-uzayı yerine deformasyon-uzayı üzerinden yapılmaktadır. Total deformasyon gradyanı C FTF (FeFp )T(FeFp ) Fp CeFp T ≡ = = şeklinde Lee ayrıştırması tarzında dikkate alınmakta, Şek.1, daha sonraki işlemlerde ise plastik akma şartı, tutarlılık şartı ve evolüsyon denklemleri kullanılmaktadır. Bu noktada Fe ve Fp nin birer nokta fonksiyonu olduğunu ve gerçek deplasman gradyanlarını göstermediğini hatırlamak gerekir [4], [8], [10].Sonuç olarak genel formülasyonla deformasyon uzayında hem serbest enerjinin ayrıştırılmaksızın kullanılmasının mümkün olduğu gösterilmiş ve hem de maddesel gerilme tansörü için bünye denklemi elde edilmiştir.In finite plasticity, free energy is usually decomposed into two portions with the first part representing elastically stored energy, while the second part representing plastic energy which is blocked in the dislocations. The second part is a function of internal variables [6] only ,while the first part is a function of observable variables. Material time derivative of the free energy density, ψ& , is then evaluated properly and then substituted into the Clausius396 Duhem inequality by usual operations. In this study we do not decompose the free energy ; instead we take the total deformation tensor C into general consideration, as in continuum formulation format. Plasticity is taken into account by Lee decomposition of the deformation gradient while vicosity is incorporated into the formulation as in Kelvin-Voigt materials. namely, we take C FTF (FeFp )T(FeFp ) Fp CeFp T ≡ = = and employ yield condition and consistency relation along with the evolution equations. At this point it is worth to remember that Fe and Fp are not true deformation gradient, they are Paff forms [4], [8] [10]. As a result, we have not only shown that the free energy can be employed without decomposing it into two parts , but also we have obtained constitutive equation for the material stress tensor

Dönme Hareketi Verilen Rijit Silindirik Bir Tankta Sıvı Çalkantısının Deneysel İncelenmesi

Bu çalışmada, değişik sıvı derinlikleri ve halka perdeler için, silindirik bir tank içindeki sıvı çalkantısından dolayı oluşan basınç ve serbest su yüzeyi değişimleri deneysel olarak incelenmiştir. Çalışmanın temel amacı, dönme etkisiyle silindirik tanklarda oluşan çalkantı problemini incelemek ve tankın içinde bulunan çeşitli noktalardaki dalga ve basınç değişimlerini üç boyutlu etkileri de dikkate alarak ölçmektir. Bu amaçla, kısmi dolu silindirik bir tankta sıvı çalkantısının doğrusal olmayan davranışını ve sönümlenme karakteristiğini ortaya koyacak bir deney düzeneği tasarlanmıştır. Bu deney düzeneğinde hem perdesiz hem de çeşitli sönümleyici perde tasarımları test edilmiştir. Böylece, ele alınan perde düzenlemelerinin göreceli avantajları incelenmiş , tank doluluk oranı, dönme periyodu ve dönme açısı sistematik olarak değiştirilerek bunun hidrodinamik yükler üzerindeki etkisi araştırılmıştır. Sıvı derinliği arttıkça sığ su etkisinin oluştuğu ve dalga enerjisinin hidrolik sıçrama ve dalga kırılması gibi nedenlerle azaldığı görülmüştür

Enhancing Fairness of Visual Attribute Predictors

The performance of deep neural networks for image recognition tasks such as predicting a smiling face is known to degrade with under-represented classes of sensitive attributes. We address this problem by introducing fairness-aware regularization losses based on batch estimates of Demographic Parity, Equalized Odds, and a novel Intersection-over-Union measure. The experiments performed on facial and medical images from CelebA, UTKFace, and the SIIM-ISIC melanoma classification challenge show the effectiveness of our proposed fairness losses for bias mitigation as they improve model fairness while maintaining high classification performance. To the best of our knowledge, our work is the first attempt to incorporate these types of losses in an end-to-end training scheme for mitigating biases of visual attribute predictors. Our code is available at https://github.com/nish03/FVAP.Comment: Camera Ready, ACCV 202

Atipik hipofiz adenomu olgularının insidansı, hormonal dağılımı ve postoperatif takibi

AMAÇ: Hipofiz adenomu tanısı ile operasyon uygulanan olgularımızdan patoloj ik tanısı atipik hipofiz adenomu olanların görülme sıklığı, hormonal aktivitesi ve postoperatif takipleri araştırılmıştır. YÖNTEM ve GEREÇlER: Kliniğimizde Ocak 2009 - Mayıs 2012 tarihleri arasında endoskopik endonasal transsfenoidal yolla opere edilen 146 hipofiz adenomu olgusundan WHO 2004 kriterlerine göre patoloj isi atipik hipofiz adenomu olarak saptanan 13 olgu çalışmaya dahil edildi. BUlGULAR: Histoloj ik olarak 133 hasta tipik hipofiz adenomu (%91,1), 13 hasta ise atipik hipofiz adenomu (%8,9) idi. Bu hastaların 10 tanesi erkek (%76,9), 3 tanesi kadındı (%23,1). Yaş dağılımı 27 ile 80 arasında idi (ortalama 52.7). Dokuz olgu nonsekretuar adenom (%69,3), 3 olgu prolaktinoma (%23,1), 1 olgu ise somatostatinoma (%7,6) idi. Dört olguda hipofizer apopleksi mevcuttu (%30,7). Tipik hipofiz adenomlu hastalardan 11 tanesinde nüks saptanırken (%8,2), atipik hipofiz adenomlu olgulardan ise 5 tanesinde nüks adenom (%38,4) nedeniyle tekrar operasyon yapıldı. SONUÇ: Atipik hipofiz adenomları iyi bir patoloj ik inceleme yapıldığında çok da nadir görülen adenom tipi değildir. Tümör rekürrensinde tek başına belirleyici olmamakla birlikte tipik adenomlara göre çok daha yüksek oranda rekürrense neden olduğu unutulmamalıdır. Bu yüzden bu hastalarda total tümör eksizyonu, eğer mümkün olmuyorsa postoperatif daha yakın takip ile ek tedavi uygulamalarının kullanılması gereklidir.AIM: To assess the incidence, hormonal activity and postoperative follow up of the cases that are histopathologically diagnosed as atypical pituitary adenoma (APA) in our series. MATERIAL and METHODS: In this study, 13 atypical pituitary adenoma cases, by the WHO 2004 criteria, among the 146 pituitary adenoma patients operated on in our clinic between January 2009 and May 2012 by endoscopic endonasal transsphenoidal approach were included. results: In histological studies, 133 cases were diagnosed as typical pituitary adenoma (91.1%) and 13 cases were APAs (8.9%) of which 10 were male (76.9%) and 3 were female (23.1%), ranged between 27 and 80 (mean 52.7) ages. Histopathological distribution of APAs was 9 non- secretory adenomas (69.3%), 3 prolactinomas (23.1%) and 1 somatostatinoma (7.6%). Asymptomatic pituitary apoplexy was diagnosed in 4 cases (30.7%). Eleven cases of typical pituitary adenomas (8.2%) and 5 cases of the atypical pituitary adenomas (38.4%) were re-operated due to tumor recurrences. CONCLUSION: Accurate histopathological examination shows that atypical pituitary adenoma is not a rare disease. Although it is not the only determinant, APAs are more prone to recurrence than typical adenomas. In our opinion, if total resection is not possible for the patients with APA, close postoperative follow up and additional curative therapy modalities are needed

Determination of macro and trace element levels of serum, tears, saliva, and hair samples in kilis goats with icp-ms

This study is focused on the evaluation of macro and trace elements concentration including sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), copper (Cu), zinc (Zn), selenium (Se), nickel (Ni), titanium (Ti), manganese (Mn), cobalt (Co), and chromium (Cr) of the serum, saliva, tears, and hair samples in Kilis goats. The study involved 33 goats without clinical signs of disease. Individual serum, saliva, tears, and hair samples from each goat were collected for element quantifications through the inductively coupled plasma mass spectrometry (ICP-MS) method after acid digestion in a microwave system. Element concentrations varied and depended on the sample type. The most predominant element in serum and saliva samples was Na (3559±55.2 and 3265±53.6 mg/L, respectively), followed by K>Ca>Mg. Potassium was the most abundant element analyzed in tears and hair samples (3506±305 and 4664±100.5 mg/L, respectively). The major trace element was Fe in all sample types except hair samples. Nickel was detected only in serum samples (83.9±6.35 μg/L) and Mn was detected only in hair samples (12903±3142 μg/L). In all samples, Co was below the detection limit. There was a significant correlation of some elements between serum and hair (Na, K, Mg, Cu), tears and hair (K, Mg, Fe), serum and tears (K) samples. Trace elements concentration did not pose a risk for deficiency or excess. It was concluded that tears and saliva are potential alternative materials for element analysis and simultaneous tears, saliva, and hair along with serum could be useful in predicting the inorganic metabolic status of goats

An exploratory study on destination personality and image of Antalya

Destinasyonlara atfedilen kişilik özellikleri ve destinasyon imajı algılarının keşfedilmesi, küreselleşen dünyada sürdürülebilir bir rekabet avantajı yaratmaktadır. Bu bağlamda bu çalışmanın temel amacı, Antalya destinasyon kişiliği ve imajına yönelik algıları ortaya çıkarmaktır. Keşfedici bir yaklaşımla durum çalışması deseninde planlanan bu araştırmada çoklu turizm paydaşlarından elde edilen veriler, nitel araştırma yöntemi ile analiz edilmiştir. Çalışma kapsamında gerçekleştirilen içerik analizi sonucunda Antalya destinasyonu ile ilişkilendirilen olumlu kişilik özellikleri “canlı, çağdaş, çok yönlü, hümanist ve samimi” olarak toplam beş boyutta ortaya çıkarken, olumsuz kişilik özellikleri ise “metalaşmış, karışık, çıkarcı ve depresif” olmak üzere dört boyutta ortaya çıkmıştır. Bunun yanı sıra, destinasyon imajına yönelik bulgular Antalya’nın işlevsel ve psikolojik destinasyon özellikleri boyutunda oldukça zengin verilere sahip olduğunu göstermektedir.The discovery of personality traits and image perceptions attributed to destinations creates a sustainable competitive advantage in the globalizing world. In this context, the main objective of this study is to reveal the perceptions associated with destination personality and image of Antalya. Applying case study based on exploratory qualitative research method, the researchers obtained the data from the multitourism stakeholders. As a result of the content analysis, the positive personality traits associated with the Antalya destination were found out as "dynamic, modern, versatile, humanist and sincere" while negative personality traits appeared as "commodified, mixed, self-seeker and depressed". In addition to this, the findings regarding the image of the destination indicate that Antalya has a very rich range of functional and psychological destination features.No sponso

A qualitative study on identification of Antalya destination personality

Uluslararası Antalya Kongresi (1. : 2019 : Antalya, Türkiye)Destinasyonlara atfedilen kişilik özelliklerine ilişkin algıların keşfedilmesi küreselleşen dünyada sürdürülebilir bir rekabet avantajı yaratmaktadır. Bu bağlamda bu çalışmanın temel amacı, Antalya destinasyon kişiliğine ilişkin algıları ortaya çıkarmaktır. Keşfedici bir yaklaşımla durum çalışması deseninde planlanan bu araştırmada çoklu turizm paydaşlarından elde edilen veriler, nitel araştırma yöntemi ile analiz edilmiştir. Araştırma periyodu boyunca elde edilen soru formları, atılımcıların mesleklerine göre tasnif edilerek kapsamlı bir içerik analizine tabi tutulmuştur. Bu kapsamda veriler, anahtar kelimeler yardımıyla kodlamalara tabii tutulmuş ve sonrasında kategorilere ayrılarak çözümlenmiştir. Sonuç olarak destinasyon kişiliğine ilişkin ana temalar ile bunlara bağlı alt temalar oluşturularak tekrar sıklığına göre sınıflamalar elde edilmiştir. Çalışma kapsamında gerçekleştirilen içerik analizi sonucunda Antalya destinasyonu ile ilişkilendirilen olumlu kişilik özellikleri “canlı, çağdaş, çok yönlü, hümanist ve samimi” olarak toplam beş boyutta ortaya çıkarken, olumsuz kişilik özellikleri ise“metalaşmış, karışık, çıkarcı ve depresif” olmak üzere dört boyutta ortaya çıkmıştır.Identification of personality traits attributed to destinations creates a sustainable competitive advantage in the globalizing world. In this context, the main objective of this study is to reveal the perceptions associated with destination personality of Antalya. Researchers obtained the data from the multi-tourism stakeholders by applying case study based on exploratory qualitative research method. The questionnaires obtained during the research period were classified according to the participants' professions and subjected to a comprehensive content analysis. In this context, the data were coded with the help of key words, and then categories have been formed. As a result, the main themes and sub-themes related to the destination personality have been created and classified according to their frequencies. As a result of the content analysis, the positive personality traits associated with the Antalya destination were found out as "dynamism, modern, versatile, humanist and sincere" while negative personality traits appeared as "commodified, mixed, self-seeker and depressed".No sponso

Intrahospital Transport Practice in Pediatric Intensive Care Units

Introduction:Critically ill children often require transport during diagnosis and treatment procedures during intensive care hospitalization. With this study, it was aimed to evaluate the practice of transport and the problems encountered during transport in pediatric intensive care units in Turkey.Methods:A questionnaire consisting of 18 questions was filled in with internet access by the head nurses of the pediatric intensive care unit, who agreed to participate in the study. Responses to questions about the characteristics of the participating centers, transport practices, problems encountered during transport, interventions and the registration system were evaluated.Results:A total of 29 tertiary pediatric intensive care units from 8 provinces in Turkey were included in the study. The mean number of beds was 14. In most pediatric intensive care units, 5 to 10 patients (51.7%) were transferred within 1 week. It was observed that the most patients were transported to the inpatient service (89.7%), followed by the operating room (69%). There was a protocol for patient transport in 69% of the units. The transport decision was made by the responsible specialist physician at a rate of 96.6%. 65% of the participants stated that the transport was recorded on a form. Transports were accompanied by 93% nurses, 86% allied health personnel, and 79% doctors. In 20 centers (69%), transport was possible with an invasive mechanical ventilator and 11 (37.9%) with a non-invasive mechanical ventilator. The most common problem encountered during transportation was the inadequacy of the physical conditions of the hospital (48.3%). There were 4 (13.8%) participants who encountered problems during patient transport in the last week. It was stated that the oxygen tube was depleted in one of them, and respiratory arrest developed in another patient.Conclusion:In this study, it was shown that; In our country, there are significant differences in intrahospital transport conditions, transport teams, equipment used during transport between centers. Transport standards should be established and these should take into account the conditions of our country. For these, compliance and monitoring mechanisms should be established

The effect of renin-angiotensin blockers on COVID-19 related mortality: A tertiary center's experience

Background: The first reports on coronaviruse disease 2019 (COVID-19) revealed an exaggerated mortality rate in hypertensive patients. In this regard, concerns about angiotensin-converting enzyme (ACE) inhibitors’ and angiotensin-receptor blockers’ (ARBs) have been aroused. Our aim in this study was to evaluate the potential bad outcome effect of hypertension and anti-hypertensive therapy on COVID-19. Methods: 183 patients with polymerase-chain-reaction (PCR)-proven COVID-19, who were admitted to our hospital and consulted to cardiology department between 15th of March and 15th of April 2020 were included. Data were recruited from hospital records. Results: Thirty-two out of 183 patients with COVID-19 died in hospital. Hypertension incidence was not statistically different between patients who survived and died (76 [50.3%] vs 19 [59.4%, p = 0.352]). Although the usage rate of ACEI were similar among groups, ARB usage rate was significantly higher in patients who died than survived (11 [34.4%] vs 23 [15.2%], p = 0.011). Binary regression analysis showed an association between ARBs and mortality (OR: 0.032, 95% CI 1.045–2.623, p = 0.032). Conclusion: Our study confirmed previous concerns regarding a potential harmful effects of ARBs on COVID-19 related mortality.Kontext: První zprávy o onemocnění koronavirem v roce 2019 (coronavirus disease 2019, COVID-19) ukazovaly na zvýšenou mortalitu jedinců s hypertenzí, což vyvolalo obavy ohledně užívání inhibitorů angiotenzin konvertujícího enzymu (ACEI) a blokátorů receptoru AT1 pro angiotenzin II (ARB). Cílem naší studie bylo posoudit možnost nepříznivého vlivu onemocnění covid-19 na závažnost hypertenze a účinnost antihypertenzní léčby. Metody: Do studie bylo zařazeno 183 pacientů s onemocněním covid-19 prokázaným PCR testem, kteří byli v období od 15. března do 15. dubna 2020 přijati do naší nemocnice a následně odesláni na kardiologickou kliniku. Údaje byly získány z nemocničních záznamů. Výsledky: Celkem 32 ze 183 pacientů s onemocněním covid-19 zemřelo v nemocnici. Incidence hypertenze se mezi pacienty, kteří přežili a zemřeli, statisticky významně nelišila (76 [50,3 %] vs. 19 [59,4 %]; p = 0,352). I když podíly pacientů užívajících inhibitory ACE byly v obou skupinách podobné, léčiva ze skupiny ARB užívalo statisticky významně více pacientů, kteří zemřeli, než těch, kteří přežili (11 [34,4 %] vs. 23 [15,2 %]; p = 0,011). Binární regresní analýza prokázala souvislost mezi užíváním ARB a mortalitou (OR: 0,032; 95% CI 1,045–2,623; p = 0,032). Závěr: Naše studie potvrdila původní obavy týkající se možných škodlivých účinků lékové skupiny ARB na mortalitu v souvislosti v onemocněním covid-19

Peroxisome proliferators-activated alpha agonist treatment ameliorates hepatic damage in rats with obstructive jaundice: an experimental study

<p>Abstract</p> <p>Background</p> <p>Peroxisome proliferators-activated receptor alpha (PPARα) activation modulates cholesterol metabolism and suppresses bile acid synthesis. This study aims to evaluate the effect of short-term administration of fenofibrate, a PPARα agonist, on proinflammatory cytokines, apoptosis, and hepatocellular damage in cholestasis.</p> <p>Methods</p> <p>Forty male Wistar rats were randomly divided into four groups: I = sham operated, II = bile duct ligation (BDL), III = BDL + vehicle (gum Arabic), IV = BDL + fenofibrate (100 mg/kg/day). All rats were sacrificed on 7^thday after obtaining blood samples and liver tissue. Total bilirubin, aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP), gamma-glutamyl transferase, (GGT), tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1 β), and total bile acid (TBA) in serum, and liver damage scores; portal inflammation, necrosis, bile duct number, in liver tissue were evaluated. Apoptosis in liver was also assessed by immunohistochemical staining.</p> <p>Results</p> <p>Fenofibrate administration significantly reduced serum total bilirubin, AST, ALT, ALP, and GGT, TNF-α, IL-1 β levels, and TBA (<it>P </it>< 0.01). Hepatic portal inflammation, hepatic necrosis, number of the bile ducts and apoptosis in rats with BDL were more prominent than the sham-operated animals (<it>P </it>< 0.01). PPARα induction improved all histopathologic parameters (<it>P </it>< 0.01), except for the number of the bile duct, which was markedly increased by fenofibrate therapy (<it>P </it>< 0.01).</p> <p>Conclusion</p> <p>Short-term administration of fenofibrate to the BDL rats exerts beneficial effects on hepatocellular damage and apoptosis.</p