1,721,093 research outputs found
Deformation and densification behaviours of nickel-based superalloy during hot isostatic pressing
No full textHot isostatic pressing of nickel-based superalloys has important applications for manufacturing near-net shape parts such as turbine disks and jet engine parts, which have to operate at high temperatures. Finite element modelling can be used to predict deformation and densification behaviour of such superalloys. Thus, the cost and time of trial and error to obtain the required geometry of the part can be reduced, such that near-net shape parts can be manufactured more economically. Numerical simulations were carried out by implementing the model of ElRakayby and Kim into Abaqus-FEA. The model parameters (relative density functions f and c) for the nickel-based superalloy were obtained from the creep response and compressive strength of porous and solid powder compacts at high a temperature. The agreement between finite element calculations and the experimental data was good for densification, shape change and density distribution of nickel-based superalloy during hot isostatic pressing. [GRAPHICS]111sciescopu
Finite element implementation of dislocation-density-based crystal plasticity model and its application to pure aluminum crystalline materials
No full textA new time-integration algorithm is presented for a dislocation-density-based crystal plasticity model. This includes a monolithic iterative scheme in which stresses were solved simultaneously with dislocation densities based on the fully backward Euler method for the integration of the constitutive model. Furthermore, the heuristic convergence criterion based on the slip resistance, instead of dislocation densities, together with the stresses is employed to circumvent stability issues. A closed form of the consistent tangent moduli is also derived. The constitutive models and time-integration procedures have been implemented as a user-subroutine UMAT of a finite element program Abaqus. Representative comparisons between the numerical predictions and experimental data are then given to verify the robustness and stability of the current implementation of the dislocation-density-based crystal plasticity model. It is demonstrated that finite element calculations reproduce well the anisotropic hardening response of differently oriented pure aluminum single crystals under tension and the variation of pile-up patterns according to different initial crystallographic orientations during nanoindentation. Furthermore, the numerical procedure was used to predict the deformation response of the aluminum multicrystalline specimen under simple shear. Non-uniform deformation fields by the digital image correlation method and surface profiles by the shadow Moire method were well reproduced by numerical predictions. In addition, the effect of the initial crystallographic orientation and the interaction effects among different crystals on the deformation response of the multicrystal are addressed.112sciescopu
Two subunits of mannose permease, II-PMan and II-MMan, of Escherichia coli mediate coliphage N4 infection.
No full textMutant strains of Escherichia coli that lack one or all of the intact components of mannose permease do not support the growth of phage N4. Complementation experiments using three recombinant plasmids containing DNA fragments coding for the subunits of mannose permease revealed that among the three component subunits, II-PMan and II-MMan alone are sufficient to confer N4 sensitivity
Duodenal perforation in a puppy with canine parvovirus infection
No full textCopyright and/or publishing rights held by the Canadian Veterinary Medical Association.A 2-month-old puppy was brought to a veterinary hospital with diarrhea, vomiting, and anorexia. The test for canine parvovirus was positive, and she was hospitalized for supportive care. Her gastrointestinal symptoms initially improved; however, vomiting and lethargy developed again in the second week of hospitalization. Abdominal ultrasonography results were suspicious of a duodenal perforation. Cytology of the abdominal effusion confirmed septic peritonitis; therefore, emergency exploratory laparotomy was performed. The surgery was successful, and the puppy recovered fully. When symptoms recur or deteriorate in patients with parvoviral infection, surgically curable complications may be disregarded if supportive therapy is continued without additional investigative examinations. This report highlights the usefulness of abdominal ultrasound in conjunction with fluid cytology to identify subsequent complications when the clinical signs of parvovirus deteriorate. Key clinical message: This case report demonstrates duodenal perforation as a complication of parvoviral infection. Abdominal ultrasonography and peritoneal fluid cytology can be crucial for the early recognition of intestinal complications requiring immediate successful perioperative treatment. Perforation duodénale chez un chiot infecté par le parvovirus canin. Un chiot de 2 mois a été amené dans un hôpital vétérinaire avec de la diarrhée, des vomissements et de lanorexie. Le test de dépistage du parvovirus canin était positif et lanimal a été hospitalisé pour des soins de soutien. Ses symptômes gastro-intestinaux se sont initialement améliorés; cependant, des vomissements et une léthargie se sont à nouveau développés au cours de la deuxième semaine dhospitalisation. Les résultats de léchographie abdominale étaient suspects dune perforation duodénale. La cytologie de lépanchement abdominal a confirmé une péritonite septique; par conséquent, une laparotomie exploratrice durgence a été réalisée. Lopération a été un succès et le chiot sest complètement rétabli. Lorsque les symptômes réapparaissent ou saggravent chez les patients atteints dune infection parvovirale, les complications soignables chirurgicalement peuvent être ignorées si le traitement de soutien est poursuivi sans examens dinvestigation supplémentaires. Ce rapport souligne lutilité de léchographie abdominale en conjonction avec la cytologie du liquide péritonéal pour identifier les complications ultérieures lorsque les signes cliniques associés au parvovirus se détériorent.Message clinique clé :Ce rapport de cas démontre une perforation duodénale comme complication dune infection parvovirale. Léchographie abdominale et la cytologie du liquide péritonéal peuvent être cruciales pour la détection précoce des complications intestinales nécessitant un traitement per-opératoire immédiat réussi.(Traduit par Dr Serge Messier).N
Effect of glass container encapsulation on deformation and densification behavior of metal powders during hot isostatic pressing
No full textHot isostatic pressing process consolidates metal powders to produce filly dense parts with complex geometries. Deformation behavior of compacts during hot isostatic pressing process typically is anisotropic for powders encapsulated in metal containers. Therefore, post-processing processes are required to fabricate the parts with required shape and dimension. This paper reports the effect of glass container encapsulation on deformation and densification behavior of 316 L stainless steel powder and nickel-based superalloy powder during hot isostatic pressing. Finite element calculations from Abaqus - finite element analysis (FEA) were compared with measured deformed shapes of powder compacts. Finally, samples deformed in glass containers were compared with those in metal containers to study the capabilities of glass containers to form near-net-shape parts. Glass containers transmitted all the pressure applied to the compacts and did not induce the Mises stress to the compacts that leads to homogeneous distribution of relative density over the compacts. Glass containers showed more homogeneous densification and uniform deformation of compacts compared to the conventional metal containers.11Nsciescopu
빔포밍 방법 및 이를 위한 장치
No full textThe present invention relates to a method for performing beamforming by using circular array antenna comprising a plurality of antennas, and a device therefor, and to a method and a device therefor, the method comprising the steps of: determining the number of operating antennas for a specific beam pattern; selecting at least one antenna among the plurality of antennas by using the determined number of operating antennas; and transmitting a signal through the selected at least one antenna, wherein the step of determining the number of operating antennas determines the number of operating antennas by using the inverse number of the square of the vertical beam width of the specific beam pattern
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Microstructure evolution of novel Sn islands prepared by electrodeposition as anode materials for lithium rechargeable batteries
No full textWe describe the striking irreversible volume expansion of micron-sized Sn anodes with brand-new Sn islands prepared by electrodeposition.</p
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
