333,292 research outputs found
Comparison of Mechanical Properties of Unidirectional and Woven Carbon, Glass and Aramid Fiber Reinforced Epoxy Composites
No full textIn this study, mechanical behavior of epoxy composite reinforced by unidirectional and woven fiber is investigated experimentally. In the preparation of composite samples woven shaped glass, aramid and carbon fibers and unidirectional shaped glass and carbon fibers were used. Tension, compression and shear tests were carried out to determine mechanical properties of composites. It is seen from the test results, that unidirectional carbon fiber shows better performance than the glass fiber. Mechanical properties of 0 degrees-oriented unidirectional fiber are better than those of 90 degrees-oriented unidirectional fiber. Mechanical properties of aramid-fiber-reinforced composite are higher than those of glass and carbon fiber, when the woven types of fibers are considered
Effects of Pre-Forming Process and PVC Foam Reinforcement on the Deformation Behavior of Aluminum Tube under Axial Loading
No full textIn this study, the effects of pre-forming and foam reinforcement on the axial compression behavior of circular thin-walled aluminum tubes were experimentally investigated. Compression tests were performed in a computer controlled test machine at the cross-head speed of 1 mm/s. Pre-forming has changed the folding behavior of tube and increased the energy absorbing capacity 1.26 times that of empty tube. The PVC reinforcement has increased the energy absorbing capacity 1.22 times. PVC reinforcement increases the stability of tube wall deformation; hence it positively affects the energy absorption. The energy absorbing capacity of pre-formed and PVC foam reinforced tubes increase approximately 1.4 times that of empty tube. It was however shown that the reinforcement and pre-forming had no significant effect on the maximum load
Investigating the effect of the concentration of Fluoride on the reproduction of S. Mutans
No full textThe bacterium S. Mutans is known as the bacterium which is one of the
reasons of the cavities in humans mouth. It basically combines with sugar and this
makes the bacterium to adhere onto the teeth and after this the cavities begin to
occur. To prevent the cavities, there is a substance called fluoride. Almost every
toothpaste includes this substance and it fights against the S. Mutans by combining
the inhibitor part to the bacterium. Some experiments have been done showing the
effect of the concentration of the fluoride on S. Mutans. However there isn’t enough
experiment which shows the exact effect of the concentration of the fluoride on the
reproduction of S. Mutans. As a result the research question of this study is; how
does the amount of fluoride effect the reproduction of S. Mutans on the teeth
surface?
Throughout the experiment it was found that when the concentration of the
fluoride was increased the concentration of the bacteria was decreased. The greatest
concentration of the bacteria was observed when there is no fluoride concentration in
petri dishes, it was 0,527 od±0,005. In addition to that the lowest concentration of S.
Mutans was observed when the fluoride concentration was the greatest (2000±0,5
ppm), the mean concentration of the bacteria was 0,173 od±0,005 which is the lowest
concentration in the experiment. In addition to that a decrease was observed in the
concentration of the bacteria when the fluoride concentration was increased, which
shows the experiment is suitable with the hypothesis. On the other hand the results
of the annova test also shows that the experiment is meaningfull with a p value which
is smaller that 0.05. The result of the experiment shows that the fluoride has an effect
on the reproduction of the bacteria and the regression in the decrease of the bacteria
is directly proportional with the concentration of the fluoride
A land information system for Turkey - a key to the country's sustainable development
No full textThis paper describes the development by the General Directorate of
Rural Services (GDRS) of a land information system for Turkey,
namely the National Soil and Water Information System. It is of
great significance for the modern state of Turkey as, prior to its
establishment in 1999 under the Turkish Agricultural Research
Project, there was no definitive, national technological information
resource underpinning land and water resource management. The
system will underpin the operational and research responsibilities
of the Directorate in combating some of the pressing contemporary
environmental concerns in Turkey, including wind and water
erosion, waterlogging, sodicity and salination of the soil resource.
The complex process of compiling the first national digital soil map
will be among the initial tasks, as well as establishing a national
infrastructure for distributing the information amongst GDRS
managers and scientists. With the proposed accession of the
Turkish Republic to the European Union, alignment of the National
Soil and Water Information System with European standards and
protocols will prove to be an important facet of its ongoing
development
Séminaire « Raison(s) pratique(s) » : Katia GENEL
No full textLe jeudi 11 février, de 17h à 19h, le Séminaire "Raison(s) pratique(s)" accueillera Katia GENEL (Université Paris 1 Panthéon-Sorbonne) qui donnera une conférence intitulée : « Honneth et les maux de la vie sociale moderne. Réflexions sur l’actualisation du modèle hégélien » Pour s’inscrire : https://evento.univ-paris1.fr/survey/seminaire-raison-s-p...-l8qe865
Genel Sağlık Sigortası ve Gelir Testi: Statü Eşitsizliğinden Gelir Eşitsizliğine
No full textHealth and social security system of Turkey underwent a significant restructuring process in 2000’s. While Health Transformation Program - put in practice in 2003fundamentally changed the organizational structure of health services; the social security reform – initiated in 2004- was embodied in two basic laws: Law on Social Security Institution no. 5502 combined existing social security institutions (Social Insurances Institution, Social Insurances Institution for Tradesmen and Craftsmen and Other Self Employed and The Retirement Fund) under a single institution. Afterwards, a social security law (The Law on Social Insurances and Universal Health Insurance) that is covering everyone with whom social insurance relation can be established and which is claimed to provide coherence of norm and standards regarding social security rights was enacted2000’li yıllarda Türkiye’de sağlık ve sosyal güvenlik alanında önemli bir yeniden yapılandırma süreci yaşandı. 2003 yılında uygulamaya konulan Sağlıkta Dönüşüm Programı sağlık hizmetlerinin örgütlenme biçimini temelden değiştirirken, 2004 yılında başlatılan sosyal güvenlik reformu çalışmaları 2006 yılında çıkartılan iki temel kanunda somutlaştırıldı: 5502 sayılı Sosyal Güvenlik Kurumu Kanunu mevcut sosyal güvenlik kurumlarını (Sosyal Sigortalar Kurumu-SSK, Esnaf ve Sanatkarlar ve Diğer Bağımsız Çalışanlar Sosyal Sigortalar Kurumu- Bağ-Kur ve TC Emekli Sandığı) tek çatı altında birleştirdi. Ardından sosyal sigorta ilişkisi kurulabilen herkesi kapsayan ve sosyal güvenlik haklarına ilişkin norm ve standart birliği getireceği ileri sürülen bir sosyal sigorta kanunu (5510 sayılı Sosyal Sigortalar ve Genel Sağlık Sigortası Kanunu) çıkartıldı.Genel Sağlık Sigortası (GSS), sağlık ve sosyal güvenlik alanındaki bu yeniden yapılandırmanın ortak bileşenidir ve sosyal güvenlik sisteminde paradigmatik bir dönüşüme yol açan 5510 Sayılı Sosyal Sigortalar ve Genel Sağlık Sigortası Kanunu’nun içerisinde düzenlenmiştir. Sağlık hizmetlerinin finansmanının genelleştirilmesi mantığı çerçevesinde düzenlenen GSS, finansman açısından sosyal sigorta modeli üzerine inşaa edilmiştir ve Türkiye’de yaşayan herkesi zorunlu olarak sisteme dâhil etmektedir. Sistemdeki herkes, sağlık finansman yönteminin bir sonucu olarak ya doğrudan prim ödeme suretiyle ya da adına devlet tarafından prim ödenmesi koşuluyla, sağlık hizmetlerine erişebilmektedir. Buna göre; hangi statüde olurlarsa olsunlar (işçi, bağımsız çalışan veya kamu görevlisi) çalışanlar prime esas kazançları üzerinden prim ödemektedir. Çalışmayan, geliri olmayan ve ödeme gücü bulunmayanların primlerinin devletçe karşılanması öngörülmüştür. Gelir testi, bu kişilerin tespit edilerek çalışmayan ancak geliri/ödeme gücü olanlardan ayrılmasını sağlamaya yönelik teknik işlemi ifade etmektedir.Bu çalışma, genel sağlık sigortasının genelleştirilmesinin aracı olarak gündeme gelen gelir testi uygulamasını konu edinmektedir. Çalışmada, önce genel sağlık sigortasında primleri devlet tarafından karşılanacak kişileri belirlemekte başvurulan gelir testinin, gelir göstergelerine dayalı hedefleme tekniği olduğunun altı çizilecektir. Daha sonra, genel sağlık sigortasının finansman yöntemi ve temel özellikleri ele alınacaktır. Bu çalışmada, genel sağlık sigortasının finansman yöntemi ve kurumsal örgütlenmesinin, sağlık hizmetine erişimde gelir temelli bir tabakalaşmaya yol açtığını ileri sürecek ve gelir testinin bu eşitsizliğin inşasındaki rolünü tartışacaktır
FE simulation of plastic collapse and geometrical factors affecting the bending response of a tubular aluminum beam
No full textIn this study, bending response of circular aluminum tube and factors affecting collapse behaviour were investigated by FE simulations. Geometrical parameters such as wall tube thickness, tube diameter, support distances, punch diameter and material properties were considered in analyses systematically. The results of analyses revealed that local buckling plays an important role on collapse load and buckling displacement is directly proportional to tube diameter, regardless of D/t and yield strength of tube material. The ratio of buckling displacement to tube diameter corresponds to 40 % of tube diameter. Moreover, an attempt was made to construct an equation as a function of D, t and yield strength for estimating collapse load. Finally, ANOVA test was used to analyze the influence of some parameters such as diameter of tube, wall thickness and yield strength. It is found from the test that the most significant factor on maximum load is wall thickness (79.6 %)
Three Point Bending Behavior of Woven Glass, Aramid and Carbon Fiber Reinforced Hybrid Composite Tube
No full textIn this study, bending behavior of hybrid composites reinforced by different type of fibers is investigated experimentally. In the preparation of composite samples with different number of layers having the same thickness and woven shaped glass, aramid and carbon fibers are used and three-point bending test is carried out to determine bending behavior. It is seen from the test results that, regardless of fiber type, the load bearing capacity and energy absorption capability are increased by increasing layer number. As a result of evaluation of hybrid composites containing different fibers with respect of load-carrying capability and energy absorbing capacity, aramid-fiber reinforced composite with 2 and 4 layer provides better performance. T + 2GF + 2CF + 2AF specimen can be preferred in between 10 layered hybrid tubes and T+ 2GF+ 2AF+ 6CF and T+ 2GF+ 2CF+ 6AF specimens in 10 layered hybrid tubes. Load carrying capacity of hybrid tubes increased 7 times and energy absorbing capacity 9.6 times, respectively
Bending response of hybrid composite tubular beams
No full textThe influence of inner and outer reinforcements on the bending performance of a thin walled aluminum tube was investigated. Polymeric materials (PA6, PP) and glass/carbon fiber reinforced epoxy were considered to form the composite beam for the inner and outer reinforcement, respectively. The experimental results indicated that the outer reinforcement with a [0(2)/90(3)] fiber orientation layout increased the collapse load by a factor of 4.5 and 5.3. In the hybrid composite beam (HCB), load carrying capacity (LCC) increased a maximum of 14 times. Load carrying capacity of HCB is 2.5 times higher than the steel tube that is used in automotive industry. (C) 2013 Elsevier Ltd. All rights reserved
Simulation of nonlinear bending behavior and geometric sensitivities for tubular beams with fixed supports
No full textIn this study, the bending characteristics of thin-walled (D/t=30) tubular beams with fixed supports are systematically investigated for different beam lengths and diameters. Bending behavior of the beam is simulated using the finite element method, in which elasto-plastic material, large-deformation and contact are included. Stress distribution is monitored by FE analyses during bending simulation. Also, load carrying and energy absorption capacities of the tubular beams having different geometrical combinations are compared with each other. The results of finite element (FE) analyses indicate that the deformation characteristics and load carrying capacities of the beam strongly depend on the diameter. From the load-displacement curve, three distinct regions were observed and the associated deformation characteristics were identified. There is a noticeable correlation between the energy absorption and transition displacements for the ranges of geometric parameters coved in this study. It is concluded that the presented simulation results can provide significant contribution to the design of side-door impact beams and passive safety research. (C) 2011 Elsevier Ltd. All rights reserved
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