Comparison of experimental and finite element analysis results of a sheet metal prototype vehicle door hinge in X, Y and Z directions

In this study, the geometric differences which have a significant effect on the simulation results of the sheet metal prototype vehicle door hinge have been revealed. This geometric difference was examined by finite element simulations and experimental tests for the loads in the X, Y and Z directions specified in the UNECE R11 regulation. As a result, the curves of the finite element simulations and the experimental tests compared for each direction were examined and it was concluded that the compatible model with the experimental tests of the sheet metal prototype vehicle door hinge was 3D scan model.Keywords: Finite element simulation, UNECE R11 regulation, Vehicle door hinge, 3D scan, Cad model.

Isolated subclinical right ventricle systolic dysfunction in patients after liver transplantation

Although hemodynamic alterations in end-stage liver disease (ESLD) and its association with porto-pulmonary hypertension have been well-established, the long-term effects of ESLD on RV systolic function in patients without porto-pulmonary hypertension remain disregarded. Here we aimed to assess the long-term effect of ESLD on RV function and its relationship with the use of NSBBs and clinical, laboratory and imaging parameters in end-stage liver disease. The use of NSBBs is still controversial due to concerns about reduced cardiac contractility and the possibility of increased mortality. Thirty-four liver transplant recipients were included. Demographic characteristics, laboratory and baseline echocardiography measures were obtained. Patients were recalled for transthoracic echocardiographic evaluation after transplantation. Right ventricle dysfunction was identified by having at least one value below the reference levels of RV S', or TAPSE. Isolated subclinical RV dysfunction was observed at 20.6% of the sample population. The present study demonstrates hemodynamic circulation in cirrhosis and increased preload and afterload might have long-term effects on RV function, even the lack of porto-pulmonary hypertension. These findings underline the significance of cardiac function follow-up in cirrhotic patients after transplantation. In this study, patients treated with propranolol seemed to have better RV function and less gastrointestinal bleeding. We speculated that preoperative propranolol treatment might help preserve RV function by providing RAS suppression, improving endothelial function and hyperdynamic circulation seen in ESLD. This potential protective relationship between the use of propranolol and RV function might improve mortality or graft-failure during OLT and after liver transplantation in patients with cirrhosis

Production and characterization of Al2024/SiC Composites with high SiC reinforcement

Bu çalışmada, ağırlıkça %10, %20 ve %40 SiC takviyesi içeren Al2024/SiC parçacıklarının mekanik öğütme (MÖ) yöntemiyle üretimi ve üretilen bu parçacıkların sıcak presleme (SP) yöntemiyle sıkıştırılması gerçekleştirilmiştir. Yapı içerisinde değişen ağırlık oranlarında (%10, 20 ve 40) SiC toz takviyesinin morfoloji, mikro yapı, element analizi, sertlik ve yoğunluk özellikleri üzerindeki etkileri araştırılmıştır. Deneysel çalışmalar sonucunda MÖ işlemi ile elde edilen homojen parçacıklar sayesinde mikro yapıda homojen bir element dağılımı gözlemlenmiştir. Ancak, yapıda ağırlıkça artan SiC toz miktarının porozite oluşumuna neden olduğu belirlenmiştir. Ağırlıkça %10, %20 ve %40 SiC içeriğine sahip kompozit numunelerin % bağıl yoğunluk değerleri sırasıyla %99.060, %98.301 ve %95.252 olarak ölçülmüştür. Yapıdaki SiC tanecik takviyesinin ağırlığının artmasıyla sertlik değerlerinde çok yüksek bir artış gözlenmiştir. Ağırlıkça %10, %20 ve %40 SiC toz içeren Al2024/SiC kompozit malzemeler için sertlik değerleri sırasıyla 177.23 HV(0.5), 250.617 HV(0.5) ve 316.67 HV(0.5) olarak ölçülmüştür.In this study, the production of Al2024/SiC particles containing 10%, 20% and 40% by weight SiC reinforcement by mechanical milling (MM) method and the compaction of these produced particles by hot pressing (SP) method were carried out. The effects of SiC particle reinforcement in varying weight ratios (%10, 20 and 40) in the structure on morphology, microstructure, elemental analysis, hardness and density properties were investigated. As a result of the experimental studies, a homogeneous elemental distribution was observed in the microstructure thanks to the homogeneous particles obtained by the MM process. However, it was determined that the amount of SiC particles increasing in weight in the structure caused the formation of porosity. The % relative density values of the composite samples with 10, 20 and 40 wt% SiC contents were measured as 99.060%, 98.301% and 95.252%, respectively. A very high increase in hardness values was observed with the increase in weight of SiC particle reinforcement in the structure. Hardness values were measured as 177.23 HV(0.5), 250.617 HV(0.5) and 316.67 HV(0.5) for Al2024/SiC composite materials containing 10, 20 and 40 wt% SiC particles, respectively

Cepstral Peak Point Analyses of Patients Recovering from Supraglottic Laryngectomy

Objective:The aim of this study is to evaluate smoothed cepstral peak point and laryngostrobosopic results in patients who underwent supraglottic laryngectomy.Method:Ten patients who underwent transcervical supraglottic laryngectomy with bilateral modified radical neck dissection, and who completed at least 12 months of follow-up, were included. All patients underwent laryngostroboscopic evaluation at study commencement; glottal closure and mucosal wave pattern were examined. Voice records were taken at fundamental frequency and smoothed cepstral peak point were analysed. Voice handicap index-10 was requested to be completed. Ten healthy individual constituted control group. Results were compared.Results:The mean smoothed cepstral peak points were 1.53-5.91 in the supraglottic laryngectomy group and 4.6-6.06 in controls, a significant difference. The fundamental frequency ranged from 174.49 to 197.25 Hz in the supraglottic laryngectomy group and from 118.57 to 197.61 Hz in the control group, also a significant difference. Laryngostroboscopic evaluation revealed no significant between-group differences in closure, but the mucosal waves differed significantly. Voice handicap index was significantly lower in supraglottic laryngectomy patients.Conclusion:Supraglottic laryngectomy reduces smoothed cepstral peak point and affects the mucosal wave, reducing voice quality

The vascular plant flora of Pazaryeri (Bilecik) and environs

Araştırma alanı Pazaryeri (Bilecik) ve çevresini kapsamakta olup Davis’in kareleme sistemine göre A2 ve B2 kareleri içinde yer almaktadır. 2013-2014 yılları arasında araştırma alanından floranın belirlenmesi için 2472 adet bitki örneği toplanmıştır. Toplanan bitki örnekleri herbaryum tekniklerine uygun olarak preslenip kurutulmuştur. Floristik liste APG III sistemi esas alınarak düzenlenmiştir. Yapılan teşhisler sonucunda çalışma bölgesinde; 61 familya, 312 cins, 532 tür ve tür altı damarlı bitki taksonu tespit edilmiştir. Araştırma alanındaki bitki taksonlarının fitocoğrafik bölgelere dağılımı ise şöyledir; %9.09’u İran-Turan, %12.50’i Akdeniz ve %10.79 Avrupa-Sibirya elementi. Çok bölgeli veya fitocoğrafik bölgesi bilinmeyenlerin oranı ise % 67.61’dir. Bölgedeki endemizm oranı %9.19’dur.The research area includes Pazaryeri (Bilecik) and its enviroment, and it occurs in the A2 and B2 square according to the grid system of P.H. Davis. To investigate the flora, 2472 specimens have been collected during the field seasons of 2013-2014. The specimens have been prepared according to the relevant herbarium techniques. The floristic list follows the APG III. At the end of identifications of the specimens 532 taxa belonging to 312 genera (61 family) have been determined. Phytogeographical distribution of the taxa are Irano-Turanian (9.09%), Mediterranean (12.50%) and Euro-Siberian (10.79%) with their percentage of. Pluriregional or phytogeographically unknown taxa is 67.61%. The endemism ratio of the areas is 9.19%

Changes in electrocardiographic p wave parameters after cryoballoon ablation and their association with atrial fibrillation recurrence

Background: Changes in P wave parameters after circumferential pulmonary vein isolation (CPVI) have been previously identified. In this study, we aimed to determine the changes in P wave parameters surface electrocardiogram (ECG) after cryoballoon ablation (CBA) for atrial fibrillation (AF) and evaluate their relationship with AF recurrence. Methods: Sixty-one patients (mean age 53 ± 11 years, 50.8% male) with paroxysmal AF who underwent CBA were enrolled. A surface ECG was obtained from all patients immediately before the procedure, and repeated 12 hours after the procedure. P wave amplitude (Pamp), P wave duration (Pwd), and P wave dispersion (Pdis) values in preprocedural and postprocedural ECGs were measured and compared. Recurrence rates of AF in 3, 6, and 9 months following ablation were recorded for all patients. Changes in P wave parameters were compared between patients with and without AF recurrence. Results: Compared to preprocedural measurements, Pamp (from 0.58 ± 0.18 mV at baseline to 0.48 ± 0.17 mV, P 0.05). Conclusion: Pamp, Pwd, and Pdis parameters exhibited significant decrease after CBA compared to preprocedural measurements. Decreased Pamp was shown to be a predictor for good clinical outcomes following CBA

Varfarine bağlı cilt nekrozu: Eski bir soruna yeni bir çözüm

We present two cases of skin necrosis occurring after initiation of warfarin therapy, bpth of wich were safely treated with novel oral anti-coagulants (NO-ACs). The first case is a 52-years-old male, seen after a transient ischemic event

Determining Simulation Parameters of Prototype Door Hinge for Correlation between Simulation and Experimental Results in United Nations Economic Commission for Europe Regulation No: 11 Tests

In this study, the simulation parameters of the door hinge were investigated in the Z direction to have a correlation between the experimental test and simulation. Tests and simulations were conducted according to the United Nations Economic Commission for Europe Regulation No: 11. The simulation parameters, which are the friction coefficient of contacts, the effect of bush material assignment and effect of production imperfections, were examined respectively by utilizing the implicit solver of Ansys Mechanical Workbench 18 and the force-displacement curves were compared with experimental test results in order to decide the optimal settings of parameters. In a conclusion friction coefficient 0.2, non-linear bush material and realistic geometry model were considered as the optimal parameter settings for correlated Finite Element Model of the hinge

Farklı yüzey ve çekirdek malzemelerine sahip sandviç panel kompozitlerin mekanik özelliklerinin incelenmesi

Bu çalışmada, otomotiv sektöründe taşıyıcı elemanlardan olan şasi malzemesinin mukavemet değerlerini yükseltirken ağırlığını düşürmek amacıyla şasi malzemesi olarak sandviç panel teknolojisinin kullanılabilirliği araştırmak amaçlanmıştır. Yüzey malzemeleri olarak; karbon elyaf ve cam elyaf takviyeli polyester kompozit ile alüminyum plaka kullanılırken, çekirdek malzemeleri olarak; alüminyum bal peteği, polipropilen (PP) bal peteği ve polietilen terafitalat (PET) sert köpük kullanılmıştır. Yüzey kompozit malzemeleri, cam ve karbon elyaf kumaşlarının katmanlı olarak polyester reçinesi ile ıslatılarak el yatırma ve basınçlı kalıplama metoduyla üretilmiştir. Sandviç plakaların soğuk preste 50 bar basınç altında 720 dk. boyunca kürünü tamamlaması sağlanmıştır. Sandviç kompozitler, yüzey ve çekirdek malzemelerinin epoksi bant ile birleştirilerek ve sıcak preste 90 °C’de 30 dk. ve 120 °C’de 60 dk. 3 bar basınç altında bekletilerek üretilmiştir. Üretilen sandviç panel kompozitlerden standartlara uygun olarak; eğilme, yüzey ve kenar doğrultusunda basma numuneleri alınıp eğilme ve basma deneylerine tabi tutulmuştur. Deney sonuçlarına göre, sandviç panellerde çekirdek malzemelerinin yüzey malzemelerine kıyasla panel mekanik özelliklerinde daha belirgin değişimler oluşturduğu belirlenmiştir. Çekirdek malzeme olarak eğilme dayanımı ve kenara basma dayanımı açısından PET çekirdek malzemesi, eğilmede elastikiyet ve yüzeye basma mukavemeti açısından alüminyum bal peteği en iyi sonuçları göstermiştir. Bununla birlikte, PP köpük malzemeleri ile üretilen sandviç paneller ise diğer çekirdek malzemelerden üretilenlere göre önemli oranda yüksek uzama oranı göstermiştir