3,134 research outputs found
On the plastic collapse of horizontal saddle supported storage vessels
No full textThe present paper summarises a comprehensive programme of work on collapse loads of horizontal cylindrical saddle supported storage vessels. A programme of tests was conducted on 40 model vessels that included both welded and loose saddles. Different collapse behaviours were observed depending largely on the radius to thickness ratio of the vessels. A range of theoretical approaches were explored and compared with the experimental results. The best theoretical comparison was then used to conduct a parametric survey covering a total of 218 cases. The results of the survey have been presented in the form of simple design graphs
On using Directional Information for Parameter Space Decomposition in Ellipse Detection
No full textIn this paper we use the parametric polar representation to extend the application of edge directional information from circle to ellipse extraction. As a result we obtain a mapping which decomposes the parameter space required for ellipse extraction into two independent sub-spaces and one final histogram accumulator. The mapping includes the tangent of the angle of the first and second directional derivatives. These tangents are computed by considering edge direction at two border points. We show that the use of gradient information for parameter space decomposition avoids the intensive point labelling imposed by geometric constraints used by other approaches
Horizontal saddle supported storage vessels - theoretical and experimental comparisons of plastic collapse loads
No full textThe safe design and operation of pressure equipment and pressure systems is key to much of the infrastructure in any present-day industrial society. This book presents an amalgam of best practice from a range of international specialists, as well as highlighting new areas that require research and development. In May 2002, pressure equipment took a major step forward with the emergence of the first edition of the new European Standard EN13445. Pressure Equipment Technology; Theory and Practice not only describes and analyses the status of the new Standard (providing underpinning data) but primarily it seeks to provide new light and present new information on many of the areas where there is insufficient coverage in EN13445 or other Standards. The information is presented in a variety of ways in order to make it useful not only for the specialist but for the general reader as well. The researcher in pressure vessel technology will find here a comprehensive and up-to date picture on many important and vital topics that need to be considered. The non-expert will also find a variety of different analysis approaches that will give interest in a whole spectrum of pressure equipment and storage vessels. The papers and information included in this volume give expert guidance on a variety of important topics that must be understood if appropriate design of pressure equipment is going to be undertaken. These include, Piping and Finite Element Analysis Saddles - Plastic Collapse Loads Vessel Ends and Eccentric Loads Containment Vessels Explosive Loading Welding and Fatigu
Horizontal saddle supported storage vessels - a parametric study of plastic collapse loads
No full textPrevious work by the present authors compared various theoretical methods with simple experiments for the plastic collapse load on end supported vessels loaded centrally by rigid saddles. It was found that the best agreement was obtained by using an elastic-plastic finite element analysis approach. In the present paper the elastic-plastic method has been used to examine the effect of various geometric parameters on the collapse load. A symmetrical model which replicated the geometric features of the experiments can be used to give an indication of the effect of specific isolated geometric variables but for others and for the purposes of undertaking a full parametric survey the model was modified to reflect an actual twin saddle supported vessel
The effects of smoothies on enamel erosion: an in situ study
No full textAims: To measure, in vitro, the pH and titratable acidity (TA) of various soft drinks and to assess the effect of smoothies on erosive tooth surface loss of enamel following a 21-day pH cycling protocol using an in situ model. Methods: The inherent pH of various soft drinks was measured using a pH meter. The TA was determined by titration with NaOH. An upper removable appliance capable of retaining two enamel slabs was constructed and worn by 14 volunteers. The drinks under test were Innocent® strawberries and bananas smoothie and citric acid. Participants were instructed to dip the appliance in the test solutions extra-orally five times daily for two minutes for 21-days. Measurements of enamel loss were made by surface profilometry and microhardness. Results: Diet Coke was found to be the most acidic drink (pH=2.61) while Innocent® mangoes and passion fruit smoothie was the least (pH=3.9). With regard to TA, Innocent® blackberries, strawberries and blackcurrants smoothie had the highest TA requiring 10.8 mol of NaOH to reach pH 7.0 while citric acid required only 3.1 mol of NaOH to reach the same pH value. The mean tooth surface loss following exposure to citric acid and Innocent® strawberries and bananas smoothie was 28.43 μm (S.D±10.25) and 2.88 μm (S.D±2.13) respectively. Citric acid caused a significantly greater tooth surface loss compared to smoothie. A statistical significant difference (change) in indentation length and enamel microhardness was found before and after exposure to test materials. Citric acid caused significantly greater difference (change) in indentation length and enamel microhardness compared with smoothie. Conclusion: Smoothies are acidic and have high TA levels. Innocent® strawberries and bananas smoothie had an erosive potential to the teeth. However, its erosive effect was significantly less compared to citric acid after 21-days pH cycling protocol using an in situ model
Genome-wide association study of primary tooth eruption identifies pleiotropic loci associated with height and craniofacial distances
No full text30.04.14 KB. Ok to add published version to spiral, OA pape
A speech portrait of our contemporary in A.S. Kushner's lyrics
No full textThe article is devoted to the speech image of the author in A.S. Kushner's poetry. Combining various socially marked colloquial units with traditional poetic means forms individual style of the author and creates a vivid image of our time
Pilares cerâmicos em implantodontia: uma revisão da literatura
No full textTCC (graduação) – Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, OdontologiaUm grande desafio na implantodontia é a obtenção de qualidade estética ideal em restaurações implantossuportadas na região anterior. A maioria dos intermediários transmucosos utilizados para reter as próteses sobre implante é composto por titânio ou outros metais. Porém, atualmente, para se alcançar excelência estética, pode-se lançar mão da combinação de coroas em cerâmica pura com pilares cerâmicos, obtendo-se melhor translucidez para a prótese sobre implante do que aquela obtida com pilares metálicos e coroas metalo-cerâmicas. Através deste método torna-se possível eliminar problemas comuns das restaurações anteriores, tais como: cor, brilho metálico através dos tecidos periimplantares e o perfil de emergência. Os dois materiais comumente utilizados na fabricação dos pilares cerâmicos são alumina e zircônia. Estudos recentes demonstram que os resultados estéticos favoráveis e o menor risco funcional estimulam o uso crescente destes materiais.The implant-supported single-tooth restoration in the incisor region represents an outstanding esthetic challenge to the dental specialist. Most of the abutments used to retain implant-supported restorations are made of titanium or other metals. However, nowadays, to achieve aesthetic excellence, we can use the combination of all-ceramic crowns with ceramic abutments, providing better translucency for the prosthesis than obtained with metallic abutments and metal-ceramic crowns. By this method, it becomes possible to eliminate common problems of restorations in incisors region, such as color, metallic sheen through peri-implant tissues and the emergence profile. The materials used in the manufacture of ceramic abutments are alumina and zirconia. Recent studies have shown that favorable esthetic results and lower functional risk can be achieved with the use of these materials
Product mix of České dráhy, a.s.
No full textBakalářská práce se zaměřuje na společnost České dráhy, a.s. a její služby poskytované v rámci širokého portfolia produktů všem cestujícím. V první části práce se autor zaměří na všeobecné informace o nástrojích marketingového mixu. Ve druhé části tyto nástroje aplikuje na produkty a služby společnosti České dráhy, a.s., zejména pak na prvky marketingového mixu, kterými jsou 4P, 5P, 7P, SWOT analýza a nástroje 4C. V poslední části dojde k vyhodnocení navržených produktů na základě dotazníkového šetření. Navrhované produkty, které budou respondentům prezentovány, vznikly na základě briefingu se zástupcem Českých drah, a.s. a se zaměstnanci cateringové společnosti JLV, a.s.The Bachelor thesis focuses on the company České dráhy, a.s. and on its services, which are promoted in wide portfolio of products to all customers. In the first chapter the author focuses to general information about tools of Marketing Mix. In the next chapter are these tools applicated to products and services of České dráhy, a.s., mainly to the points of Marketing Mix, which are following tools 4P, 5P, 7P, SWOT analysis and tools of 4C. The conclusion deals with proposed products, which are based on questionnaire results. Proposed results, which will be presented to respondents, were created thanks to briefing with the representative of České dráhy, a.s. and with employees of catering company JLV, a.s.Dopravní fakulta Jana PerneraProblematiku řešenou ve své bakalářské práci dokázal student odpovídajícím způsobem obhájit. Prokázal schopnost samostatné práce. Na doplňkové otázky reagoval pohotově, se znalostí věci a bez závažných nepřesností je zodpověděl.Dokončená práce s úspěšnou obhajobo
A Lagrangian sub-grid model for the dispersion of clouds of tracers
No full textTurbulence models are expected to satisfy the conflicting requirements of accuracy and computational efficiency. Here we discuss a new model that was recently developed in order to accurately and efficiently describe the dynamic of a clouds of tracers particles in Large Eddy Simulations of homogeneous and isotropic turbulent flows. The models incorporates the multi-scale nature of time and space turbulent velocity correlations that are essential in order to correctly reproduce the relative dispersion of multi-particle clouds. The model can be seen as an off-grid solver for the Eulerian velocity field at the positions of a given number of Lagrangian tracers that self-consistently move with it. Extensions to non homogeneous and isotropic turbulence as well as to the dynamics of particles will be discussed
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