Refined turbulence models for simulation of IC -engine cylinder flows

Turbulence and turbulent mixing are two of the most important factors that influence the efficiency and emissions level in internal combustion (IC) engines, particularly for diesel engines. This study has been performed with the premise to accurately predict in-cylinder turbulence by employing the large eddy simulation (LES) technique. In order to assess the turbulence scales involved correctly, a review of measured and computed scales relevant to IC engines is conducted. An assessment of these is made in comparison with the self-imposed scales of the engine itself. This assessment focuses on the influence of combustion, compression ratio, initial conditions and numerical mesh on predicted turbulence scales. It was found that the turbulence scales predicted by employing the commonly used k-epsilon turbulence model were in good qualitative agreement with experimental observations and could be used as a guide to determine the degree of resolution needed in LES.;To establish a base to improve existing Reynolds averaged Navier-Stokes (RANS) models, a comparative study of the commonly used RANS models applied to IC engines was conducted, using an experimental benchmark case, which is an isothermal, incompressible flow within a piston-cylinder arrangement motored without combustion. This study has lead to a new hybrid turbulence model, namely, the Smagorinsky based eddy viscosity (SEV) model, which is self-adjusting between an eddy viscosity model and subgrid-scale model, depending on the grid size, continuously from RANS to LES. It was tested against the above-mentioned experimental benchmark. The predicted velocity profiles and streamlines are in good agreement with experiments. The new model is a viable alternative to the k-epsilon model in predicting the mean flowfield in IC engines.;Furthermore, the relative importance of the turbulence generation mechanisms in IC engines has been studied using LES. First, the compression and expansion strokes of a piston-bowl configuration are thoroughly investigated using a fine 2-D axisymmetric grid and a 3-D grid. Next, the flow dynamics during the intake stroke has been examined using a full 3-D configuration of an engine with valves and a typical bowl. The results show that a significant portion of the inertial sub-range in the energy spectra can be resolved using a moderately fine grid with about 300,000 vertices. The calculated spectra display about the same energy content up to f ≈ 104 Hz, which is on the same order of maximum frequency resolved in typical experiments. It is shown via the LES technique, that significant turbulence is likely to be generated by a carefully designed bowl; and that the more energetic intake turbulence generated during the intake stroke decays rapidly during the compression stroke

Global Imbalances, Current Account Rebalancing and Exchange Rate Adjustments

We analyze the global imbalances and the required adjustments for rebalancing in current accounts and real exchange rates. We set up a two-country two-sector model for the US- China with two asymmetries. First, we assume that the size of China initially is one third of the US but its size becomes half of the US in the next ten years consistent with the fast growth expectations in China. Secondly, we assume that China initially runs a net export surplus against the US. Then we quantitatively study two adjustment scenarios. First scenario,called Slow Adjustment, assumes that in the process of growth, Chinese demand composition moves more towards domestic non-tradable sector. In this case, Chinese real exchange rate appreciates gradually and net export surplus also decreases slowly. Second scenario, called Quick Adjustment, assumes that in addition to the higher non-tradable share in output, net export surplus against US goes to zero quickly in fi�ve years. In this case, net export adjustment happens quickly and real exchange rates in China also appreciate faster and at a higher rate than Slow Adjustment case. Even though, global imbalances are eliminated faste in the Quick Adjustment case, high real appreciation in China hurts importers in the US. A comparison in terms of output shows that Slow Adjustments is preferred for both countries.Global imbalances, Current accounts, Exchange rate adjustments

Cicatricial Alopecias

Primary cicatricial alopecias (PCA) are a rare group of disorders in which the hair follicle is the main target of destructive inflammation resulting in irreversible hair loss with scarring of affected lesions. Inflammation may predominantly involve lymphocytes or neutrophils. Cicatricial alopecias that mainly involve lymphocytic inflammation include lichen planopilaris, discoid lupus erythematosus, pseudopelade (Brocq), central centrifugal alopecia, alopecia mucinosa, and keratosis follicularis spinulosa decalvans. Cicatricial alopecias that are due to predominantly neutrophilic inflammation include folliculitis decalvans and dissecting cellulitis of the scalp. Acne keloidalis, acne necrotica, and erosive pustular dermatosis are cicatricial alopecias with a mixed inflammatory infiltrate

Mermer türlerinin makine öğrenmesi teknikleri kullanılarak sınıflandırılması

Doğal taşlar, insanların barınmadan silaha kadar vazgeçilmez unsurlarından bir tanesidir. Bu taş türleri içerisinde mermerler ve mermer türevli ürünler banyodan mutfağa, bahçe tasarımından küçük dekoratif ev süslerine kadar insanların sürekli tercih ettiği objelerdendir. Mermerler çıkarıldıkları bölgelere göre isimlendirilirken bu alanda uzman olarak nitelendirilen kişiler tarafından gözleme dayalı olarak türleri ve kaliteleri sınıflandırılmaktadır. Uzman kişilerin gözleme dayalı yaptığı bu sınıflandırma ekonomik anlamda risk taşımakta, iş yükünü arttırmakta ve hata oranı yüksek olabilen zorlu bir süreçtir. Bu süreçlerin hızlı, kolay ve doğruluk oranı yüksek bir dijital dönüşüme ihtiyacı bulunmaktadır. Bu çalışmada mermerlerin tür sınıflandırmasında derin öğrenme kullanılarak özellik çıkarımı yapılmıştır. Çıkarılan özellikler makine öğrenme teknikleri kullanılarak sınıflandırma uygulaması gerçekleştirilmiştir. 28 ayrı türe ait 3703 mermer ve mermer türevli doğal taş imgesinden oluşan veri seti ile yapılan uygulamanın test sonucunda DenseNet derin öğrenme modeli ve K-En Yakın Komşu metodu ile %99,7’lik sınıflandırma başarımı elde edilmiştir.Natural stones are one of the indispensable elements of people from shelter to weapons. Among these stone types, marbles and marble-derived products are among the objects that people always prefer, from bathroom to kitchen, from garden design to small decorative home decorations. While the marbles are named according to the regions where they are extracted, their types and qualities are classified based on observation by people who are qualified as experts in this field. This classification, which is made by experts based on observation, carries risks in economic terms, increases the workload and is a difficult process with a high error rate. These processes need a fast, easy and highly accurate digital transformation. In this study, feature extraction was done by using deep learning in the species classification of marbles. The extracted features were classified using machine learning techniques. As a result of the application made with the data set consisting of 3703 marble and marble-derived natural stone images belonging to 28 different species, a classification success of 99.7% was obtained with the DenseNet deep learning model and the K-Nearest Neighbor method

The pattern of malocclusion in a sample of orthodontic patients from Turkey

Objective: The objective of this study was to determine the prevalence of individual traits of malocclusion in a sample of Turkish orthodontic patients. Study design: The present study was based on the examination of dental casts, intraoral photographs and panoramic radiographs of 1507 orthodontic patients (884 females and 623 males). The relationship of the first upper and lower molars according to the Angle?s classification, overjet, overbite, crowding, spacing, posterior crossbite, scissor bite, maxillary median diastema were examined. The Pearson chi-squared and Fisher?s Exact tests were used to determine potential differences in the distribution of malocclusion when stratified by gender. Results: The study demonstrated that only 52 (3.5%) of the subjects had normal occlusion. Class I malocclusion was found in 626 (41.5%), Class II Division 1 in 435 (28.9%), Class II Division 2 in 142 (9.4%) and Class III malocclusion in 252 (16.7%) subjects of all examined. Normal overbite, normal overjet, crossbite on both sides and severe crowding in the upper dental arch were observed more frequently in females (P<.05), however, increased overbite and moderate crowding in the upper dental arch were observed more frequently in males (P<.05). Conclusion: The results of this study showed that crowding in the upper and lower dental arches in a sample of Turkish population was the most frequent of all anomalies recorded with ranges of 70.0% and 47.3%, respectively

Different View on Lichen Disease; Platelet Lymphocyte Ratio

INTRODUCTION: Lichen planus is an inflammatory dermatosis of mucocutaneous surfaces with various clinical manifestations. In this study, we wanted to investigate NLR, PLR rates and MPV values in lichen planus disease METHODS: Thirty-five patients over the age of 18 and 30 healthy controls were followed up with lichen diagnosis of my work. Leukocyte, erythrocyte, platelet, hemoglobin, platelet volume values were determined in hemogram tests. The NLR ratio was obtained by dividing the number of neutrophils by the number of lymphocytes and the TLR ratio by dividing the platelet count by the lymphocyte count. RESULTS: The mean age of the participating was 43.0+-14.1, leukocyte level was 6.7 (5.6-8.3) hemoglobin level was 14.5+-1.6, and the value of MPV was 8.6 (7.9-9.0). The platelet value was 262.1+-52.2, the neutrophil value was 3.5 (2.9-4.9), and the lymphocyte value was 2.3 (2.1-2.8). Neutrophil lymphocyte ratio 1.5 (1,0-1,9), platelet lymphocyte ratio 110.4+-29.7. Hemoglobin levels were significantly higher in males than females DISCUSSION AND CONCLUSION: This study showed that TLO, NLO and OTH values did not change in lichen patients. In spite of many expensive markers showing systemic inflammation, PLR, NLR and MPV are simple and cheap markers

A tumoral mass (local recurrence of renal cell carcinoma) causing massive intraabdominal bleeding after blunt abdominal trauma

AbstractBackgroundSolid organ injury after abdominal trauma is a common condition, however, injury of the local recurrent tumoral masses following abdominal trauma is rare. The injuries and bleeding in recurrent tumors tend to be highly serious since they are more fragile. The bleedings caused by renal cell carcinomas and by the traumatic laceration of their recurrence commonly occur in the retroperitoneum.In this report, we present a 55-year-old female patient who underwent emergency surgery due to intraabdominal bleeding and bleeding was from the recurrence of a renal cell carcinomas.Presentation of caseThe 55-year-old female patient was admitted to the emergency service with intraabdominal bleeding. Physical examination revealed tenderness in the right lower quadrant, particularly in the traumatic area. Ultrasonography and computed tomography revealed diffuse intraabdominal fluid and a ruptured bleeding mass was excised. Pathological analysis indicated that the mass was isolated local recurrence of renal cell carcinoma.DiscussionSolid organ injury caused by blunt abdominal trauma may be accompanied by tumoral laceration; however, minor bleeding may occur in cases with blunt trauma, coexistence of blunt abdominal trauma with local recurrence and massive bleeding is extremely rare.Control of bleeding is more challenging in tumoral tissues compared to normal tissues. The bleeding intraabdominal area rather than the retroperitoneal area, and this condition was attributed to the peritoneal tear caused by the trauma.ConclusionLocal recurrent tumoral masses may be the source of the intraabdominal massive bleeding after blunt trauma

MyProfessors: Mining Turkish Student Reviews

We introduce Hocalarim (MyProfessors), the largest student review dataset available for the Turkish language. It consists of over 5000 professor reviews left online by students, with different aspects of education rated on a scale of 1 to 5 stars. We investigate the properties of the dataset and present its statistics. We examine the impact of students' institution type on their ratings and the correlation of students' bias to give positive or negative feedback

The sources of al-Ḏahabī with Regard to the biographical information

Râvîlere dair yazılan klasik eserlerin, birbirlerinin devamı mahiyetinde olduğu görülür. Zehebî’nin (ö. 748/1348) ricâl eserleri de kendisinden önceki ilmî birikimi kendisinden sonrakilere aktarması bakımından önemli bir konuma sahiptir. Zira o, biyografilerde sadece râvî bilgisini aktarmaz, diğer münekkitlerden farklı olarak zengin bir kaynakçaya da yer verir. Müellifin Mîzânü’l-iꜥtidâl’i bu yönüyle incelendiğinde çok sayıda kitaba atıf yapıldığı fark edilir. Bu referanslar onun istifade ettiği kaynakları göstermenin yanı sıra hicrî VIII. asra kadar ulaşan râvî bilgisinin kendisinden nakledilidiği literatüre de işaret etmektedir. Bu makale, Mîzânü’l-iꜥtidâl’deki atıflar üzerinden Zehebî’nin kaynak tasnifini yapmayı ve ilgili referanslardaki metodunu ortaya koymayı hedeflemektedir. Aynı zamanda cerh-taꜥdîl kitaplarında tespit edilen referanslar üzerinden râvî bilgisine dair literatür hakkında yeni çalışmaların imkanını göstermeyi amaçlamaktadır. Çalışmada Zehebî’nin teliflerinde yararlandığı eserler, asıl kaynaklar ve yardımcı kaynaklar şeklinde iki kısma ayrılmıştır. Yaptığı atıfların, mevcut râvî bilgisini ihtisar etmek ve ilgili edebiyatı kayıt altına almak gibi önemli faydaları olduğu tespit edilmiştir. Ayrıca kendi kitaplarına yaptığı göndermeler, elde ettiği veriler ışığında râvî biyografilerini güncellediğini de ortaya koymuştur.Each classical biographical dictionary on narrators (ruwāt, pl. of rāwī) of ḥadīth is seen as a continuation of its predecessors. As such, al-Dhahabī’s (d. 748/1348) works occupy an important space in this genre thanks to its function to transmit the accumulated knowledge in this field to the generations lived after him. In fact, he not only relates biographical information but also, unlike other critics, incorporates in this a very rich bibliography. In addition to showing the sources he made use of, these references also point to the body of literature from which the biographical information on the narrators, which reaches well into the 8th century of the Hijra, had been transmitted. Through the references mentioned in Mīzān al-Iʿtidāl, the present paper aims at classifying the sources of al-Dhahabī while also bringing out his methodology in these references. It also aims to show the possibility of using the references found in the works of jarḥ-taʿdīl to conduct new studies on the literature about biographical information of the narrators. The works which al-Dhahabī made use of in his compilations are classified into two categories in this work, namely primary sources and secondary sources. The present work found that the references he makes had such benefits as summarizing the accumulated biographical information about the narrators and recording the relevant literature. Moreover, the references he makes to his works demonstrate that he updated biographical information on the narrators in the light of the information he had acquired

Local Bone Marrow Renin-Angiotensin System and Atherosclerosis

Local hematopoietic bone marrow (BM) renin-angiotensin system (RAS) affects the growth, production, proliferation differentiation, and function of hematopoietic cells. Angiotensin II (Ang II), the dominant effector peptide of the RAS, regulates cellular growth in a wide variety of tissues in pathobiological states. RAS, especially Ang II and Ang II type 1 receptor (AT1R), has considerable proinflammatory and proatherogenic effects on the vessel wall, causing progression of atherosclerosis. Recent investigations, by analyzing several BM chimeric mice whose BM cells were positive or negative for AT1R, disclosed that AT1R in BM cells participates in the pathogenesis of atherosclerosis. Therefore, AT1R blocking not only in vascular cells but also in the BM could be an important therapeutic approach to prevent atherosclerosis. The aim of this paper is to review the function of local BM RAS in the pathogenesis of atherosclerosis