Numerical Modeling of Stagnation Flows over Porous Catalytic Surfaces

In this book, stagnation flows on a catalytic porous plate is modeled one-dimensionally coupled with multi-step surface reaction mechanisms and molecular transport (diffusion and conduction) in the flow field and in the porous catalyst. Internal and external mass transfer limitations as well as possible reaction routes in the catalyst are investigated for CO oxidation, WGS reaction, partial and steam reforming of methane over Rh/Al?O?

Numerical Modeling of Stagnation Flows over Porous Catalytic Surfaces

In this book, stagnation flows on a catalytic porous plate is modeled one-dimensionally coupled with multi-step surface reaction mechanisms and molecular transport (diffusion and conduction) in the flow field and in the porous catalyst. Internal and external mass transfer limitations as well as possible reaction routes in the catalyst are investigated for CO oxidation, WGS reaction, partial and steam reforming of methane over Rh/Al₂O₃

Numerical Modeling of Stagnation Flows over Porous Catalytic Surfaces

In this thesis, a stagnation flow on a catalytic porous plate is modeled one-dimensionally coupled with multi-step surface reaction mechanisms and molecular transport (diffusion and conduction) in the flow field and in the porous catalyst. Internal and external mass transfer limitations as well as possible reaction routes in the catalyst are investigated for CO oxidation, WGS reaction, partial and steam reforming of methane over Rh/Al2O3

Numerical Simulation of Methane and Propane Reforming Over a Porous Rh/Al2_{2}O3_{3} Catalyst in Stagnation-Flows: Impact of Internal and External Mass Transfer Limitations on Species Profiles

Hydrogen production by catalytic partial oxidation and steam reforming of methane and propane towards synthesis gas are numerically investigated in stagnation-flow over a disc coated with a porous Rh/Al$_{2}$O$_{3}$ layer. A one-dimensional flow field is coupled with three models for internal diffusion and with a 62-step surface reaction mechanism. Numerical simulations are conducted with the recently developed computer code DETCHEM$^{STAG}$. Dusty-Gas model, a reaction-diffusion model and a simple effectiveness factor model, are alternatively used in simulations to study the internal mass transfer inside the 100 µm thick washcoat layer. Numerically predicted species profiles in the external boundary layer agree well with the recently published experimental data. All three models for internal diffusion exhibit strong species concentration gradients in the catalyst layer. In partial oxidation conditions, a thin total oxidation zone occurs close to the gas-washcoat interface, followed by a zone of steam and dry reforming of methane. Increasing the reactor pressure and decreasing the inlet flow velocity increases/decreases the external/internal mass transfer limitations. The comparison of reaction-diffusion and Dusty-Gas model results reveal the insignificance of convective flow on species transport inside the washcoat. Simulations, which additionally solve a heat transport equation, do not show any temperature gradients inside the washcoat

Homonymy theory and divine attributes in Ibn Rushd

Felsefe ve mantık ilişkisi klasik felsefede lazım-melzum ilişkisi içerisinde ele alınmış ve biri olmaksızın diğerinin varlığı yadsınmıştır. Bu kadar güçlü bir ilişki kurulmasına rağmen filozofların metinlerinde mantık ilminin konu, kavram ve meselelerinin çoğu zaman zımnî bir şekilde yer aldığı görülür. Bu çalışmada mantık ilminin kelâmî ve felsefî bir mesele olan sıfatlar tartışmasında nasıl bir rol oynadığı konusu ele alınmıştır. Letâif-i kelamdan kabul edilen tevhid konusunun alt bir meselesi olarak ilahî sıfatlar, farklı boyutlarıyla İslam düşüncesinde sayısız düşünür tarafından ele alınıp tartışılmıştır. İbn Rüşd de kendisinden önceki geleneğin tartıştığı bu meseleye bigâne kalamamış ve yeni bir düzlemde, farklı bir yaklaşımla konuyu incelemiştir. Bu çalışmada İbn Rüşd’ün sıfatlar tartışmasına dair yaptığı okuma biçimi sadece müşterek lafız teorisi ile sınırlandırılmıştır. Nitekim bu yolla mantık ve felsefe ilişkisinin birbirinden kopmayan iki cüz oldukları gösterildiği gibi İbn Rüşd’ün sıfatlar bahsinde kendine özgü mantık temelli bir yaklaşımı savunduğu iddia edilmiştir. Nihai olarak İbn Rüşd’ün müşterek lafız teorisini ilahî sıfatlar bahsine tatbik etmesinin sıfatlar meselesini anlamada yeni bir imkân sunduğu gösterilmiştir.The relationship between philosophy and logic is discussed within the concomitant-the implicant (al-lazim-al-malzum) relationship in classical philosophy, and the existence of one of them is denied unless the other one exists. Despite such a strong relationship, it is seen that the subjects, concepts and issues of the science of logic are often implicitly included in the texts of philosophers. This study discusses how the science of logic plays a role in the discussion of attributes, which is a theological and philosophical issue. Divine attributes, as a sub-issue of the subject of tawhid, which is accepted as one of the fine matters of theology (Latâif-i kalâm), have been handled and discussed by numerous thinkers in Islamic thought. Similarly, Ibn Rushd could not remain ignorant of this issue discussed by the tradition before him, and examined the subject on a new level and with a different approach. In this study, Ibn Rushd’s reading style to the discussion of attributes is limited only by the theory of common words. As a matter of fact, in this way, the article shows that the relationship between logic and philosophy are two inseparable parts, and it is claimed that Ibn Rushd advocated a unique logic-based approach in the subject of attributes. Finally, it has been shown that Ibn Rushd's application of homonymy theory to the issue of divine attributes offers a new opportunity to understand the issue of attributes

Van İli Çevresi Kabuk Deformasyon Analizi ve Deprem Tehlike Değerlendirmesi

Van ili ve çevresi, bölgesinde var olan güçlü tektonik hareketler ve deformasyonların etkisi altındadır. Bu deformasyonların esas kaynağını Arabistan levhasının Anadolu levhasına göre göreceli kuzey ve kuzey batı yönlü hareketi oluşturur. Bu bağıl hareket sonucunda Bitlis Zagros Kenet Kuşağı, Doğu Anadolu ve Kuzey Anadolu Fay sistemleri bölgenin depremselliğinde önemli rol oynamaktadır. Bölgede var olan gerilme analizlerinin belirlenmesi, Van ili ve çevresinde oluşacak deprem tehlikesini daha net ortaya çıkaracaktır. Bu bağlamda bölgede var olan GPS verileri ve Global CMT kataloğundan elde edilen depremsellik verileri kullanılarak çalışma alanında deformasyon oranı tespit edilmiştir. Buna göre çalışma alanında 40 n gerinim/yıl deformasyon alanı elde edilmiş, bölgesel gerilim içerisindeki bu küçük KB-GD sıkışma bileşeninin, 2011 Van depreminde olduğu gibi deprem mekanizmasında beklenenden daha büyük bir rol oynayabileceği saptanmıştır. Bölgede hâkim olan dilatasyon mekanizması incelendiğinde ise; Van ili ve çevresinde 25 n gerinim/yıl olan kesme bileşeni Karlıova bölgesine yaklaşıldıkça 170 n gerinim/yıl mertebesine erişmektedir. 2003 yılında bu bölgede meydana gelen Mw 6.4 Bingöl depreminin sağ yanal bir yapıda olması, Kuzey Anadolu Fay mekanizmasının Van ili civarına kadar uzanabileceğini işaret etmektedir. Bu alanda meydana gelebilecek büyük ölçekte deprem, Van Ovası’nda yerel zemin koşullarına bağlı olarak, yerleşim yerlerinde potansiyel tehlike oluşturabileceği ön görülmektedir

OXIDATIVE STRESS AND SERUM S100B LEVELS IN ADOLESCENTS WITH FIRST-EPISODE DRUG-NAIVE UNIPOLAR DEPRESSION

Background: Unipolar depression is common among adolescents and has high recurrence rates. Studies conducted with adults show that oxidative stress plays a role in etiology of depression but studies with adolescent patients are limited. In addition, baseline S100B level in adult patients with depression is considered as a marker of response to treatment. The purpose of this study was to measure the levels of serum S100B, Malondialdehyde (MDA), total oxidant status (TOS), and total antioxidant status (TAS), which have not been previously investigated in adolescent patients with first-episode, drug-naïve unipolar depression, and to investigate the relationship of these parameters with disease severity and patient-specific variables. Subjects and methods: This study was conducted with 37 adolescents diagnosed with unipolar depression and 37 healthy peers. Participants were asked to fill out the Beck Depression Scale, Screen for Child Anxiety Related Disorders, and suicide probability questionnaires. After this procedure, 5 cc blood was collected from the adolescents and serum S100B, MDA, TOS, and OSI levels measured. Results: Serum S100B, MDA, TOS, and OSI levels were higher and TAS level was lower in patients than their healthy peers. There was no relationship between the patients\u27 severity of depression or suicide probability and these parameters. The serum S100B, MDA, TOS, and OSI levels of female patients were higher than their healthy peers, but the TAS level was not different. Male patients had higher TOS and OSI levels and lower TAS levels than their healthy peers. Conclusions: The results show that increased serum S100B, MDA, TOS and OSI levels may contribute to etiology of depression regardless of gender. The gender-specific increase in S100B and MDA levels, which were significantly increased in female adolescent patients but not in males, should be supported by further follow-up studies

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Müzik Türüne Uygun Reverb Estetiği

Thesis (M.A.) -- İstanbul Technical University, Institute of Social Sciences, 2017Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Sosyal Bilimler Enstitüsü, 2017It is essential to create an acoustic space for instruments, almost in every genre of music. First reason of this is about aesthetics. It is about being able to put instruments background or up front as desired. Second reason is listener’s traditions for certain genres. They shape the recording and mixing phase of the music for certain genres. The main goal of this work is to interrogate the validity of these common expectations of reverb usage for certain genres and to understand the reasons behind their existence. The secondary goal of this work is to inquire the possibility of breaking the expectations about using reverbs and to suggest new possibilities. The first stage tried to explain the terms about reverberation. A brief history of reverb is given and types of reverbs are explained. The second stage covered basic concepts of digital reverberation units. Common parameters of digital units are explained. The third stage consisted of the aesthetics of reverb. The reasons to add dimension to a mix, using reverb units on individual instruments, creative usage of reverb units are explained. The fourth stage of this work tried to collect data from three different groups of participants who are fifty-five people in total: Musicians, sound engineers, and non- musicians. Results are analyzed in this stage. The conclusion of this work presents comparison of the participants’ preferences according to playback system they used. Analysis of the questions, which have distinctive results, and their possible reasons are covered. In addition, to be able to get more reliable results, suggestions for future research are given.Enstrümanlar için akustik mekan oluşturmak neredeyse tüm müzik türleri için çok büyük önem taşır. Bunun ilk sebebi estetiktir. Enstrümanların istenilen şekilde öne çıkarılması veya arka planda bırakılmasına imkan sağlamaktır. Ikinci sebep ise dinleyicilerin belirli müzik türleri için sahip oldukları alışkanlıklardır. Bu alışkanlıklar müzik türlerine göre kayıt ve düzenleme evrelerini şekillendirir. Bu çalışmanın ana fikri belirli müzik türlerinde reverb kullanımı ile ilgili genel beklentilerin geçerliliğini sorgulamak ve bu beklentilerin varoluşlarının arkasındaki gerçekleri anlamaktır. Çalışmanın bir diğer amacı ise reverb kullanımı ile ilgi bu beklentilerin dışına çıkma olanağını değerlendirmek ve yeni imkanlar sunmaktır. Ilk bölümde reverb ile ilgili tanımlar ve terimlerin açıklanmasına çalışıldı. Reverb hakkında kısa bir tarihçe anlatıldı ve reverb türleri açıklandı. İkinci bölümde dijital reverb üniteleriyle ilgili temel kavramlar verildi. Dijital reverb ünitelerinde yaygın olarak kullanılan parametreler açıklandı. Üçüncü bölüm reverb estetiğinden oluşmaktadır. Bir mikse derinlik ekleme nedenleri, bireysel enstrümanlar üzerinde reverb kullanımı ve reverb efektinin yaratıcı kullanımları anlatıldı. Dördüncü bölümde toplamda elli beş kişi olan üç ayrı katılımcı grubundan bilgiler toplanmaya çalışıldı: Müzisyenler, ses mühendisi ve diğerleri. Bu bölümde sonuçlar analiz edildi. Bu çalışmanın son bölümü katılımcıların tercihleri kullandıkları ses sistemine göre karşılaştırma sunmaktadır. Belirgin cevapları olan sorular ve bunların olası nedenleri ele alındı. Ek olarak, daha güvenilir sonuçlar alabilmek adına, gelecek araştırmalar için tavsiyeler verildi.M.A.Yüksek Lisan