Yüzen Bir Yapının Düzenli Dalgalarda Hidroelastik Analizi

Konferans Bildirisi-- İstanbul Teknik Üniversitesi, Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2017Conference Paper -- İstanbul Technical University, Theoretical and Applied Mechanical Turkish National Committee, 2017Bu çalışmada, modal analiz prensiplerini temel alan lineer hidroelastisite teorisi konteyner tipi bir gemi için uygulanmıştır. Lineer hidroelastisite teorisinde, yapısal ve hidrodinamik problemler lineer davranış ve potansiyel akım kabulleri altında ilişkilendirilebilir. Modal süperpozisyon teknikleri serbest titreşim ve zorlamalı titreşim problemlerini verimli bir şekilde çözebilmemizi sağlar. Bu yöntem sayesinde yapısal tepki, asal titreşim şekillerindeki hareketlerin, şekil değiştirmelerin, vs. birleşimi olarak alınabilir. Bu çerçevede, öncelikle yapısal sönüm ve dış kuvvetlerin yokluğunda kuru yapının dinamik karakteristikleri yani doğal frekanslar ve karşılık gelen asal titreşim şekilleri standart sonlu elemanlar programı ile belirlenebilir. Problemin ikinci aşamasında, her bir asal titreşim şekline karşılık gelen akışkan kuvvetlerinin hareket denklemine dâhil edilmesi gerekir. Akışkanın yapıya uyguladığı hidrodinamik atalet, sönüm, geri getirme ve zorlayıcı kuvvetlerinin bulunabilmesi için sınır elemanları metodu kullanılabilir. Akışkanın ideal ve hareketinin döngüsüz olduğu kabul edilmesi halinde, potansiyel akımı tanımlayan Laplace denklemi, gerekli sınır koşullarını sağlayan bir sınır integral denklemine dönüştürülebilir. Böylelikle problem sadece geminin ıslak yüzeyi olan arayüzde tanımlı hale gelir.This study bases on modal analysis principles which means structural response considered as sum of motions and deformations at principal coordinates. Structural and hydrodynamic problems are coupled weakly by depending on linear hydroelasticity theory where structural and hydrodynamic problems regarded under the linear behavior and potential flow theory respectively. Finite element method is used for free vibration analysis of structure. Boundary element method is used to determine sea loads arise from coming and scattering waves around the floating structure as well as to determine wave loads arise from radiating waves due to ship motion. Excitation forces which effect the floating structure, can be determined by using distribution of velocity potential and radiation originated distributed velocity potential takes the effect of deep water. In this approach the structure response can be calculated under the condition of small wave steepness for regular waves

Effective Recommendation Of Reviewers For Research Proposals

In this project, we address the problem that a research funding agency may face when matching potential reviewers with submitted research proposals. A list of potential reviewers for a given proposal is typically selected manually by a small technical group of individuals in the agency. However, the manual approach can be an exhausting and challenging task, and (more importantly) might lead to ineffective selections that affect the subsequent funding decisions. This research work presents an effective automated system that recommends reviewers for proposals and helps program managers in the assignment process. This system views the CVs of the reviewers and rank them by assigning weights for each CV against the list of all the proposals. We propose an automatic method to effectively recommend (for a given research proposal) a short list of potential reviewers who demonstrate expertise in the given research field/topic. To accomplish this task, our system extracts information from the full-text of proposals and the CVs of reviewers. We discuss the proposed solution, and the experience in using the solution within the workflow of the Qatar National Research Fund (QNRF). We evaluate our system on a QNRF/NPRP dataset that includes the submitted proposals and approved list of reviewers from the first 5 cycles of the NPRP funding program. Experimental results on this dataset validate the effectiveness of the proposed approach, and show that the best performance of our system demonstrated for proposals in three research areas: natural science, engineering, and medical. The system does not perform as well for proposals in the other two domains, i.e., humanities and social sciences. Our approach performs very well in overall evaluation with 68% of relevant results, i.e., from each 10 recommendations 7 are matching perfectly. Our proposed approach is general and flexible. Variations of the approach can be used in other applications such as conference paper assignment to reviewers and teacher-course assignment. Our research demonstrates also that there are significant advantages to applying recommender system concepts to the proposal-to-reviewer assignment problem. In summary, the problem of automatic assignment of proposals to reviewers is challenging and time-consuming when it is conducted manually by the program managers. Software systems can offer automated tools that significantly facilitate the role of program managers. We follow previous approaches in treating reviewers finding system as an information retrieval task. We use the same basic tools but the goal is to find relevant people rather than searching for relevant documents. For a specific user query (proposal), the system returns a list of qualified reviewers, ranked by their relevance to the query.qscienc

Çok Kriterli Karar Verme Yöntemlerinin Gemi İnşaatı ve Gemi Makineleri Mühendisliğinde Uygulamaları

Decision-making processes are important in naval architecture and marine engineering, similar to all engineering fields. T he well-known branch of decision making is the Multi-Criteria Decision Making (MCDM) which involves both quantitative and qualitative factors. In this study, the applications of Multi-Criteria Decision Making (MCDM) methods in naval architecture and marine engineering were examined with 21 Turkish postgraduate theses and 21 English international articles. It is find out that the most frequently used MCDM method is firstly AHP and secondly TOPSIS, and the most frequently used purpose is firstly ship systems selection and secondly ship design. MCDM, a sub-field of operations research, is presented for naval architecture and marine engineers who are new and inexperienced to the subject. With this study, one another aim is to help researchers to bring original MCDM approaches to the original MCDM problems

Effectiveness of hot oil treatment on cultivated 15 year-old acacia hybrid against Coriolus versicolors, Gloeophyllum trabeum and Pycnoporus sanguineus

The effectiveness of the hot oil treatment process on 15 year old cultivated Acacia hybrid was studied. Accelerated laboratory durability studies were conducted on the hot oil treated Acacia hybrid inoculated with fungi Coriolus versicolors, Gloeophyllum trabeum and Pycnoporus sanguineus. The logs of Acacia hybrid were harvested, segregated into bottom, middle and top portions, and later were oil-heat treated in an organic palm oil at temperatures of 180, 200 and 220°C for the duration of 30, 60 and 90 min. The wood samples that were dried and ground into sawdust was air-dried again before undergoing accelerated laboratory durability tests. Untreated samples were used as control. The durability of the wood increases with an increase in temperature and duration of the treatment. The hot oil treated samples could reduce the attack of G. trabeum from 20.89%, 20.94% and 21.29% in the control samples to 0.88-4.07%, 1.22-4.84% and 1.28-4.22% at bottom, middle and top portions, respectively. The attack of C. versicolors were reduced from 26.59%, 30.28% and 34.79% in the control samples to 2.89-9.41%, 3.88-16.84 and 4.27-17.34% at bottom, middle and top portions. However, the attacked of P. sanguineus were least effective with 31.42%, 36.33% and 36.55% in control samples to 3.26-12.55%, 4.67-15.36% and 4.69-19.22% at bottom, middle and top portions. Massive colonization of mycelia occurs in vessels of the untreated Acacia hybrid wood in comparison to the hot oil treated wood when observed through scanning electron microscope

Relationship Between Acute Appendicitis and Platelet Indices in Childhood

Introduction: Appendicitis is the inflammation of the appendix vermiformis. Clinical diagnosis of acute appendicitis in children is still a problem. Platelet indices, platelet distribution width and mean platelet volume have been evaluated for some infectious and inflammatory diseases. In this study, we aimed to investigate whether platelet distribution width values and mean platelet volume were decisive for the diagnosis of appendicitis in children. Methods: In our hospital, 504 pediatric patients who presented with acute abdomen and received the diagnosis of acute appendicitis between 2011 and 2016, and 106 children living in the same region, who attended the pediatric outpatient clinics for general follow-up, were included in the study. The patient and control groups were analyzed for gender, age, platelet count, platelet distribution width and mean platelet volume. A receiver operating characteristic (ROC) curve was drawn to describe the parameters that may be statistically significant. Results: There was a significant difference in platelet distribution width and mean platelet volume values between the two groups (p14.3 fL for platelet distribution width for the diagnosis of appendicitis with a sensitivity, specificity, positive predictive value, and negative predictive value of 77.6%, 85.8%, 96.3%, and 44.6%, respectively. A cut-off value of <9.35 fL for mean platelet volume was used for the diagnosis of appendicitis with a sensitivity, specificity, positive predictive value, and negative predictive value of 78.1%, 81.1%, 95.2%, and 43.9%, respectively. Conclusion: Our results suggest that platelet distribution width and mean platelet volume may be used for the diagnosis of appendicitis in children with the sensitivity of at least 77.6% and 78.1%, respectively. Mean platelet volume and platelet distribution width, which can easily be investigated in complete blood count, may serve as markers for the diagnosis of appendicitis in children, however, further large-scale studies are needed

Cytokine Profiles in Toxoplasmic and Viral Uveitis

BackgroundUveitis is a major cause of visual impairment throughout the world. Analysis of cytokine profiles in aqueous humor specimens may provide insight into the physiopathological processes that underly retinal damage in this context MethodsUsing a multiplex assay, we determined the concentrations of 17 cytokines and chemokines in aqueous humor specimens obtained from patients with ocular toxoplasmosis or viral uveitis and compared these concentrations with those in specimens obtained from patients with noninfectious intermediate uveitis or cataract ResultsFive mediators (interleukin [IL]-8, monocyte chemoattractant protein-1, tumor necrosis factor-α, IL-4, and IL-10) were detected in >50% of patients in all groups. In contrast, IL-5 and IL-12 were specific for ocular toxoplasmosis, and granulocyte monocyte colony-stimulating factor and IL-1 were specific for viral uveitis; these mediators could present specific markers for diagnostic purposes. Interferon-γ, IL-6, and macrophage inflammatory protein-1β were common markers of ocular toxoplasmosis and viral uveitis. IL-17 was a common marker of ocular toxoplasmosis and intermediate uveitis ConclusionsWe found specific cytokine profiles for each type of uveitis, with large interindividual variations and no etiological or clinical correlations. Ocular cytokine mapping contributes to a better understanding of the physiopathology of specific forms of uveitis and provides guidance for new targeted treatmen

High fatigue scores in patients with idiopathic inflammatory myopathies: a multigroup comparative study from the COVAD e-survey

Idiopathic inflammatory myopathies (IIMs) confer a significant risk of disability and poor quality of life, though fatigue, an important contributing factor, remains under-reported in these individuals. We aimed to compare and analyze differences in visual analog scale (VAS) scores (0-10 cm) for fatigue (VAS-F) in patients with IIMs, non-IIM systemic autoimmune diseases (SAIDs), and healthy controls (HCs). We performed a cross-sectional analysis of the data from the COVID-19 Vaccination in Autoimmune Diseases (COVAD) international patient self-reported e-survey. The COVAD survey was circulated from December 2020 to August 2021, and details including demographics, COVID-19 history, vaccination details, SAID details, global health, and functional status were collected from adult patients having received at least one COVID-19 vaccine dose. Fatigue experienced 1 week prior to survey completion was assessed using a single-item 10 cm VAS. Determinants of fatigue were analyzed in regression models. Six thousand nine hundred and eighty-eight respondents (mean age 43.8 years, 72% female; 55% White) were included in the analysis. The overall VAS-F score was 3 (IQR 1-6). Patients with IIMs had similar fatigue scores (5, IQR 3-7) to non-IIM SAIDs [5 (IQR 2-7)], but higher compared to HCs (2, IQR 1-5; P < 0.001), regardless of disease activity. In adjusted analysis, higher VAS-F scores were seen in females (reference female; coefficient -0.17; 95%CI -0.21 to -13; P < 0.001) and Caucasians (reference Caucasians; coefficient -0.22; 95%CI -0.30 to -0.14; P < 0.001 for Asians and coefficient -0.08; 95%CI -0.13 to 0.30; P = 0.003 for Hispanics) in our cohort. Our study found that patients with IIMs exhibit considerable fatigue, similar to other SAIDs and higher than healthy individuals. Women and Caucasians experience greater fatigue scores, allowing identification of stratified groups for optimized multidisciplinary care and improve outcomes such as quality of life

Systemic sclerosis and COVID-19 vaccine safety: short-term insights from the global COVID-19 vaccination in autoimmune disease (COVAD) survey.

The safety profile of COVID-19 vaccines is understudied in patients with systemic sclerosis (SSc). We compared short-term adverse events (AEs) 7 days following vaccination in patients with SSc vs other rheumatic (AIRDs), non-rheumatic autoimmune diseases (nrAIDs), and healthy controls (HCs). The COVID-19 Vaccination in autoimmune diseases (COVAD) self-reporting e-survey was circulated by a group of > 110 collaborators in 94 countries from March to December 2021. AEs were analyzed between different groups using regression models. Of 10,679 complete respondents [73.8% females, mean age 43 years, 53% Caucasians], 478 had SSc. 83% had completed two vaccine doses, Pfizer-BioNTech (BNT162b2) (51%) was the most common. Minor and major AEs were reported by 81.2% and 3.3% SSc patients, respectively, and did not differ significantly with disease activity or different vaccine types, though with minor symptom differences. Frequencies of AEs were not affected by background immunosuppression, though SSc patients receiving hydroxychloroquine experienced fatigue less commonly (OR 0.4; 95% CI 0.2-0.8). Frequency of AEs and hospitalisations were similar to other AIRDs, nrAIDs, and HC except a higher risk of chills (OR 1.3; 95% CI 1.0-1.7) and fatigue (OR 1.3; 95% CI 1.0-1.6) compared to other AIRDs. COVID-19 vaccines were largely safe and well tolerated in SSc patients in the short term. Background immunosuppression and disease activity did not influence the vaccination-related short-term AEs

Pain in individuals with idiopathic inflammatory myopathies, other systemic autoimmune rheumatic diseases, and without rheumatic diseases: A report from the COVAD study

OBJECTIVES: To compare pain intensity among individuals with idiopathic inflammatory myopathies (IIMs), other systemic autoimmune rheumatic diseases (AIRDs), and without rheumatic disease (wAIDs). METHODS: Data were collected from the COVID-19 Vaccination in Autoimmune Diseases (COVAD) study, an international cross-sectional online survey, from December 2020 to August 2021. Pain experienced in the preceding week was assessed using numeral rating scale (NRS). We performed a negative binomial regression analysis to assess pain in IIMs subtypes and whether demographics, disease activity, general health status, and physical function had an impact on pain scores. RESULTS: Of 6988 participants included, 15.1% had IIMs, 27.9% had other AIRDs, and 57.0% were wAIDs. The median pain NRS in patients with IIMs, other AIRDs, and wAIDs were 2.0 (interquartile range [IQR] = 1.0-5.0), 3.0 (IQR = 1.0-6.0), and 1.0 (IQR = 0-2.0), respectively (P < 0.001). Regression analysis adjusted for gender, age, and ethnicity revealed that overlap myositis and antisynthetase syndrome had the highest pain (NRS = 4.0, 95% CI = 3.5-4.5, and NRS = 3.6, 95% CI = 3.1-4.1, respectively). An additional association between pain and poor functional status was observed in all groups. Female gender was associated with higher pain scores in almost all scenarios. Increasing age was associated with higher pain NRS scores in some scenarios of disease activity, and Asian and Hispanic ethnicities had reduced pain scores in some functional status scenarios. CONCLUSION: Patients with IIMs reported higher pain levels than wAIDs, but less than patients with other AIRDs. Pain is a disabling manifestation of IIMs and is associated with a poor functional status

COVID-19 Vaccination In Autoimmune Diseases (COVAD) Study : Vaccine Safety In Idiopathic Inflammatory Myopathies

In this study we investigated COVID-19 vaccination-related adverse events (ADEs) 7 days postvaccination in patients with idiopathic inflammatory myopathies (IIMs) and other systemic autoimmune and inflammatory disorders (SAIDs). Seven-day vaccine ADEs were collected in an international patient self-reported e-survey. Descriptive statistics were obtained and multivariable regression was performed. Ten thousand nine hundred respondents were analyzed (1227 IIM cases, 4640 SAID cases, and 5033 healthy controls [HCs]; median age, 42 [interquartile range, 30-455] years; 74% female; 45% Caucasian; 69% completely vaccinated). Major ADEs were reported by 76.3% of the IIM patients and 4.6% reported major ADEs. Patients with active IIMs reported more frequent major (odds ratio [OR], 2.7; interquartile range [IQR], 1.04-7.3) and minor (OR, 1.5; IQR, 1.1-2.2) ADEs than patients with inactive IIMs. Rashes were more frequent in IIMs (OR, 2.3; IQR, 1.2-4.2) than HCs. ADEs were not impacted by steroid dose, although hydroxychloroquine and intravenous/subcutaneous immunoglobulins were associated with a higher risk of minor ADEs (OR, 1.9; IQR, 1.1-3.3; and OR, 2.2; IQR, 1.1-4.3, respectively). Overall, ADEs were less frequent in inclusion-body myositis (IBM) and BNT162b2 (Pfizer) vaccine recipients. Seven-day postvaccination ADEs were comparable in patients with IIMs, SAIDs, and HCs, except for a higher risk of rash in IIMs. Patients with dermatomyositis with active disease may be at higher risk, and IBM patients may be at lower risk of specific ADEs. Overall, the benefit of preventing severe COVID-19 through vaccination likely outweighs the risk of vaccine-related ADEs. Our results may inform future guidelines regarding COVID-19 vaccination in patients with SAIDs, specifically in those with IIMs. Studies to evaluate long-term outcomes and disease flares are needed to shed more light on developing future COVID-19 vaccination guidelines