83 research outputs found

    500 KW Rüzgar Türbini İçin Ana Şaft Tasarımı Ve Analizi

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    Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2013Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2013Bu çalışmada, 500 kW güç üreten bir rüzgar türbinin ana şaftının tasarımı ve yapısal analizleri yapılmıştır. Ana şaftın boyutlandırılmasında yorulma kriterlerinin esas alınması gerekmektedir. Ana şaftın yorulmaya ait yük durumu ise literatürde bulunan ampirik formüller kullanılarak hesaplanmıştır. Yorulma analizlerinde şaftı çevrimsel yüklerle zorlayan rotor ağırlığının yanında rüzgar kesmesi ve kule blokaj etkisi vb. sebeplerle ortaya çıkan değişken eğilme momenti ve tork değerleri de hesaba katılmıştır. Ana şaftın kritik kesitlerindeki çap hesabı, ASME Eliptik yorulma kriteri kullanılarak sonsuz ömre göre yapılmıştır. Ana şaftın tasarımındaki kritik bölgeler şaftın yataklandığı bölge ve şaftın dişli kutusuna bağlandığı bölgedir. Ayrıca, kontrol amaçlı olarak Uluslararası Elektroteknik Komisyonu’nun (International Electrotechnical Commision) yayınlamış olduğu IEC 64100-1 standardında belirtilen yükleme şartları için ana şaftın statik analizleri ANSYS 14.5 sonlu elemanlar yazılımı kullanılarak gerçekleştirilmiştir. Şaftın sonlu eleman modeli SOLID185 elemanlar kullanılarak oluşturulmuştur. Ayrıca, ana şaft - göbek bağlantı elemanlarının analizi de bu çalışma kapsamında yapılmıştır. Sayısal ve analitik yöntemler kullanılarak elde edilen deformasyon ve gerilme sonuçları karşılaştırılmış ve iyi bir uyum olduğu görülmüştür.In this paper, the main shaft which is one of the important structural parts for a 500 kW wind turbine has been designed. The fatigue criteria has been based on sizing the main shaft. The main shafts critic desing loads have been calculated by empirical formulas which are on the literatures. Oscillation moments of the torque and the flexural moments which is created by wind share, and effect of tower, etc. have been envisaged for analytical and numerical studies. In this study, the main shaft has been designed for infinite life using with ASME Elliptic criteria. There are two critic areas which are supported and connected to the gear box. In addition Iternational Electrotechnical Commision (IEC) 64100-1 standards have been based on the critic design load cases. The main shaft and the fasteners are modeled using the finite element method. The finite element model of the shaft is designed using with SOLID185 elements. Its static analysis have been achieved with using ANSYS 14.5 software. Also a comparison of two different approximations have been mentioned in this paper. The values of analitic and numerical of deplacement and stress are compared each

    Učinak formulacijskih parametara na oslobađanje lijeka i svojstva dvoslojnih tableta koje plutaju u želucu

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    Floating dosage forms of acetylsalicylic acid, used for its antithrombotic effect, were developed to prolong gastric residence time and increase bioavailability. In the two-layer tablet formulation, hydroxypropyl methylcellulose (HPMC) of high viscosity and an effervescent mixture of citric acid and sodium bicarbonate formed the floating layer. The release layer contained the drug, direct tableting agent and different types of matrix-forming polymers such as HPMC of low viscosity, sodium carboxymethylcellulose and chitosan. Tablets were prepared using a direct compression technique. The effect of formulation variables on physicochemical and floating properties and the drug release from tablets were investigated. Floating ability was dependent on the amount of effervescent agent and gel-forming polymer of the floating layer. Drug release was prolonged to 8 hours by changing the type and viscosity of the matrix-forming polymer in the drug-loading layer and all formulations showed a diffusion release mechanism.U radu su opisane plutajuće tablete acetilsalicilne kiseline za antikoagulacijsku upotrebu s produljenim zadržavanjem u želucu i većom bioraspoloživošću. Plutajući dio tih dvoslojnih tableta sadržavao je hidroksipropil metilcelulozu (HPMC) visoke viskoznosti i efervescentnu smjesu limunske kiseline i natrijevog hidrogenkarbonata. Drugi sloj sadržavao je ljekovitu tvar, sredstvo za izravno tabletiranje i različite vrste matriksnog polimera poput HPMC niske viskoznosti, natrij-karboksimetilceluloze i kitozana. Tablete su pripravljene metodom izravne kompresije. Ispitivan je utjecaj formulacijskih varijabli na fizikokemijska i plutajuća svojstva, te oslobađanje ljekovite tvari. Plutajuća svojstva ovise o količini efervescentnih tvari i gelirajućeg polimera u plutajućem sloju. Promjenom vrste i viskoznosti polimera u matriksnom sloju s lijekom produljeno je oslobađanje ljekovite tvari na 8 sati. Iz svih formulacija ljekovita tvar oslobađala se difuzijom

    CA8 Mutations Cause a Novel Syndrome Characterized by Ataxia and Mild Mental Retardation with Predisposition to Quadrupedal Gait

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    We describe a consanguineous Iraqi family in which affected siblings had mild mental retardation and congenital ataxia characterized by quadrupedal gait. Genome-wide linkage analysis identified a 5.8 Mb interval on chromosome 8q with shared homozygosity among the affected persons. Sequencing of genes contained in the interval revealed a homozygous mutation, S100P, in carbonic anhydrase related protein 8 (CA8), which is highly expressed in cerebellar Purkinje cells and influences inositol triphosphate (ITP) binding to its receptor ITPR1 on the endoplasmatic reticulum and thereby modulates calcium signaling. We demonstrate that the mutation S100P is associated with proteasome-mediated degradation, and thus presumably represents a null mutation comparable to the Ca8 mutation underlying the previously described waddles mouse, which exhibits ataxia and appendicular dystonia. CA8 thus represents the third locus that has been associated with quadrupedal gait in humans, in addition to the VLDLR locus and a locus at chromosome 17p. Our findings underline the importance of ITP-mediated signaling in cerebellar function and provide suggestive evidence that congenital ataxia paired with cerebral dysfunction may, together with unknown contextual factors during development, predispose to quadrupedal gait in humans

    Masonry compressive strength prediction using artificial neural networks

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    The masonry is not only included among the oldest building materials, but it is also the most widely used material due to its simple construction and low cost compared to the other modern building materials. Nevertheless, there is not yet a robust quantitative method, available in the literature, which can reliably predict its strength, based on the geometrical and mechanical characteristics of its components. This limitation is due to the highly nonlinear relation between the compressive strength of masonry and the geometrical and mechanical properties of the components of the masonry. In this paper, the application of artificial neural networks for predicting the compressive strength of masonry has been investigated. Specifically, back-propagation neural network models have been used for predicting the compressive strength of masonry prism based on experimental data available in the literature. The comparison of the derived results with the experimental findings demonstrates the ability of artificial neural networks to approximate the compressive strength of masonry walls in a reliable and robust manner.- (undefined

    Gölbaşı Gölü’nün Zooplankton Biyoması ve Tür kompozisyonu (Hatay-Türkiye)

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    The species composition and biomass of zooplankton in lake Gölbaşı (Hatay, Türkiye). The zooplanktonic fauna of lake Gölbaşı was investigated in samples collected from 2 stations between May, 2001, and April, 2002. The zooplankton of lake Gölbaşı consist mainly of Cladocera, Copepoda and Rotifera groups. A total of 27 species composed of 2 Cladocerans, 2 Copepoda and 23 rotifers were identified. During the 1-year study period, the most dominant group was Rotifera. The highest number of Rotifera were observed in second station in May, 2001. Although the species belonging to Copepoda were found, except in some months, Cladocera species were only observed in the first station, November 2001. Rotifera had the highest biomass in second station in May, 2001. Lake Gölbaşı has mesotrophic-eutrophic characteristics due to the seasonal distribution of zooplanktonic organisms. However, the lake has mesotrophic characteristics due to the eutrophication index value. As a result, it will be necessary to conduct further physical and chemical analyses of the lake water to obtain more detailed information about the trophic status of the lakeGölbaşı gölünün zooplankton faunası Mayıs 2001-Nisan 2002 tarihleri arasında 2 istasyondan alınan örneklerde incelendi. Gölbaşı gölünün zooplanktonunu başlıca Cladocera, Copepoda ve Rotifera grupları oluşturmaktadır. Teşhis edilen 27 türün dağılımı ise; Cladocera (2), Copepoda (2) ve Rotifera (23)'dür. Bir yıllık çalışma sırasında baskın grup Rotifera oldu. Rotifera'nın en yüksek sayısı ise Mayıs 2001'de 2. istasyonda gözlendi. Copepoda'ya ait türler bazı aylar dışında bulunmasına rağmen, Cladocera türleri sadece Kasım 2001'de 1.istasyonda gözlendi. Rotifera Mayıs 2001'de 2. istasyonda en yüksek biyomas değerine sahipti. Gölbaşı gölü zooplanktonik organizmaların mevsimsel dağılımlarından dolayı mezotrofik-ötrofik karakteristiğe sahiptir. Buna karşılık ötrofikasyon indeks değerinden dolayı mezotrofik karakteristiğe sahiptir. Bu nedenle gölün tropik durumu hakkında daha detaylı bilgi almak için göl suyunun fiziksel ve kimyasal analizlerinin yürütülmesinin uygun olacağı düşünülmektedir

    A comparative study on two closely relative Tulipa L. taxa from NE Anatolia

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    This study presents observations on the anatomical, palynological and ecological features of Tulipa gumusanica Terzioğlu and its morphologically similar relative, T. armena Boiss. var. armena, in order to clarify their similarities and differences. We found that these taxa have some important differences with regard to anatomical, palynological and ecological features, as well as morphological traits. General anatomical traits of both examined taxa are similar, both having isolateral leaves with distinct hypodermis and a stem with distinct monolayer collenchyma close to the epidermis. However, some anatomical characters such as mesophyll width, average number of stomata on lower epidermis, and epidermal cells on upper epidermis are found to be important in delimiting these taxa. In addition, considerable differences have been observed in pollen shape and size. The species differ ecologically in that T. gumusanica prefers slightly acidic soil with low organic content in the woodland, whereas T. armena var. armena prefers slightly alkali soil with high organic content in steppe vegetation. © 2008 Springer-Verlag

    Synthesis of new 6-[4-(2-fluorophenylpiperazine-1-YL)]-3(2H)-pyridazinone-2-acethyl-2- (substitutedbenzal)hydrazone derivatives and evulation of their cytotoxic effects in liver and colon cancer cell lines

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    In this study, seven new 3(2H)-pyridazinone derivatives expected to show cytotoxic activity in liver and colon cancer cell lines were synthesized. Their structures were confirmed by the IR, 1 H-NMR, 13 C-NMR spectra and elementary analyses. Compunds V 1 -V 7 were tested on HEP3B (liver cancer) and HTC116 (colon cancer) cell lines for cytotoxicity by using MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)- 2H-tetrazolium] proliferation assay. Human fibroblast cells were used as safety control in these tests. 6-[4-(2-Fluorophenyl)piperazine-1-yl]-3(2H)-pyridazinone-2-acetyl-2-(2-chlorobenzal)hydrazone (compound V 3 ) was the most active agent with respect to HEP3B and HTC116 cell lines. © 2019, Springer Science+Business Media, LLC, part of Springer Nature
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