Efecto del tiempo de superpulso de soldadura sobre la evolución microestructural de un acero de bajo carbono

El tipo de arco Súper Pulso fue desarrollado para proporcionar una solución a los cordones de pasada de raíz de juntas a tope, en el proceso de soldadura semiautomático con protección gaseosa (GMAW). A diferencia de la soldadura por pulsos estándar, el Súper Pulso utiliza una secuencia de diferentes formas de onda de pulso para crear una forma y aspecto de cordón similar al proceso GTAW. Utiliza bajo amperaje en la fase primaria para reducir el calor aportado y más alto amperaje en la segunda fase para mejorar la penetración. La velocidad de soldadura e incluso la penetración se proporcionan durante la fase de transferencia en spray, mientras que la entrada de calor se reduce durante la segunda fase (transferencia en corto, arco corto o pulsado). Se utiliza la transferencia de spray en la fase primaria para mejorar la penetración y arco pulsado en la fase secundaria para enfriar el baño de soldadura dando menos transferencia de calor y menos distorsión al material de base. En la literatura hay poca información respecto a la relación entre las variables del Súper Pulso y las características microestructurales del metal depositado. El objetivo de este trabajo fue evaluar la influencia de los tiempos de cada fase en modo Súper Pulso, sobre las características geométricas del cordón, la dilución y la solidificación en depósitos de soldadura de aceros con bajo contenido de carbono. Para tal fin, se soldaran cordones sobre una chapa IRAM - IAS U500 - 42 - F24 variando el tiempo de fases del Súper Pulso. Sobre cortes transversales se determinó la geometría de los cordones, el grado de dilución, la microestructura y sobre cortes longitudinales las características de las zonas fundidas y afectadas. Resultados preliminares mostraron que la geometría del cordón y la solidificación estuvieron fuertemente influenciadas por los parámetros del pulso.Superpulse system was a motivation to provide a GMAW solution for root pass on steel. Unlike standard pulse welding, pulse/pulse (superpulse) uses a sequence of varying pulse wave shapes to create a bead shape and appearance similar to the GTAW process. It utilizes low amperage in the primary phase for heat reduction and higher amperage in the second phase for enhanced penetration. The welding speed and even penetration are provided during the spray arc phase, whereas heat input is reduced during pulse phase. It utilises spray arc transfer in the primary phase for enhanced penetration and pulse arc in the secondary phase, which serves to cool the weld pool for less heat transfer to the base material and less distortion. Pulsing in the second phase also allows spray type transfer to be achieved in all positions of welding. Nowadays there is scare information about the relationship between variables of procedure and microstructural characteristics of the weld metal. Therefore the aim of this work was to evaluate the influence of pulse time on the dilution and solidification of F24 steel plate. For this purpose, four coupons modifying the time of pulse were welded. On each coupon, chemical composition was determined and microstructure was studied using both optical and electronic microscopy. The dilution and microhardness of beads and phases were measured. Preliminary results show that the geometry of the bead and the solidification were strongly influenced by the pulse parameters

Cardiovascular magnetic resonance artefacts

The multitude of applications offered by CMR make it an increasing popular modality to study the heart and the surrounding vessels. Nevertheless the anatomical complexity of the chest, together with cardiac and respiratory motion, and the fast flowing blood, present many challenges which can possibly translate into imaging artefacts. The literature is wide in terms of papers describing specific MR artefacts in great technical detail. In this review we attempt to summarise, in a language accessible to a clinical readership, some of the most common artefacts found in CMR applications. It begins with an introduction of the most common pulse sequences, and imaging techniques, followed by a brief section on typical cardiovascular applications. This leads to the main section on common CMR artefacts with examples, a short description of the mechanisms behind them, and possible solutions

Orthogonally polarised shear waves for evaluating anisotropy and cracks in metals

The detection of crack-like defects using ultrasound is a problem widely studied by the non-destructive evaluation community. In this work, a technique of how to detect the presence of a crack-like defect and estimate its orientation in an anisotropic material by means of two orthogonal shear waves is presented. A detailed study of shear wave propagating and splitting at any incident angle, and its interaction with crack-like defects in anisotropic materials, is also presented. In this paper it is shown that by the use of two orthogonal shear waves with linear polarisation the authors could: 1) estimate the material level of anisotropy within approximately 0.5% of the measured value; 2) estimate the angular position of the principal shear directions of the material with respect to the orthogonal shear wave sources within ±5⁰ accuracy; 3) excite a shear wave purely polarised along one of the principal shear directions with two orthogonal shear waves placed at an arbitrary angular position; 4) detect the presence of a crack-like defect in an anisotropic material based on the back-wall echoes of two orthogonal shear waves, 5) estimate the orientation of a crack-like defect in an anisotropic material within ∼ ± 5⁰ of the theoretical value. The simulation and experimental results obtained show that the technique presented in this paper has potential to become an effective tool for crack-like defect detection and material characterisation

Shear waves with orthogonal polarisations for thickness measurement and crack detection using EMATs

The use of polarised shear waves to detect the presence of crack-like defects seems to have received little or no attention in the past. The authors believe that the main reason for this appears to be the lack of a device with the capability to excite shear waves of different polarisations. In this paper, the authors, first, present the design of an EMAT that permits the excitation of two orthogonally polarised shear waves in metallic materials by means of two coils that are orthogonal with respect to each other. This is then followed by a 3D finite element analysis of the wavefield generated by the EMAT and its interactions with crack-like defects of different sizes, positions and orientations. Then a methodology of how this EMAT can be used to simultaneously measure material thickness and detect crack-like defects in pulse-echo mode is introduced. Good agreement between the finite element simulation and experimental results was observed which makes the presented technique a potential new method for simultaneous thickness measurements and crack detection

The role of knowledge management processes in achieving tax excellence Applied research in the General Authority for Taxation

يهدف البحث إلى تسليط الضوء على عمليات إدارة المعرفة في تحقيق التفوق الضريبي للهيئة العامة للضرائب باعتبارها جهة خدمية تقدم العديد من الخدمات للمكلفين والشركات، فكلما استطاعت الهيئة تبني مفاهيم جديدة لزيادة فهم ومعرفة كيفية اهتمامها بالمكلفين من اكتساب وتنظيم ونقل المعرفة والعمل على توفير بيئة عمل مناسبة، في جذب مكلفين جدد، وبناء علاقات طويلة الأمد معهم, كلما أنعكس على الأداء والتفوق الضريبي. وتحقيقاً لذلك سوف يعتمد الباحثين في تحليل متغيراته على الاستبانة كأداة رئيسة لجمع البيانات والمعلومات. و لقد ارتأينا و من أجل تعميق الاجابة عن الاشكالية التالية بتساؤلات عدة, منها, ماهية عمليات إدارة المعرفة ومدى استعداد الهيئة العامة للضرائب للأستفادة منها?, ما أثر أبعاد عمليات إدارة المعرفة (اكتساب المعرفة , تنظيم المعرفة  , نقل المعرفة) في تحقيق التفوق الضريبي للهيئة عينة البحث , من هنا برزت أهمية البحث في هذا الموضوع من خلال التعرف على مدى تأثير عمليات إدارة المعرفة  على تحقيق التفوق الضريبي لا سيما وان الضريبة تعتبر من الموارد الرئيسة للدولة وخصوصا البلدان النامية.   The research aims to highlight the knowledge management processes in achieving tax excellence of the General Authority for Taxation as a service provider that provides many services to taxpayers and companies. The more the Authority can adopt new concepts to increase understanding and knowledge of how they are interested in the acquisition, organization and transfer of knowledge and work to provide an appropriate work environment, In attracting new taxpayers, and building long-term relationships with them, whenever reflected on performance and tax excellence. To this end, research in the analysis of its variables will depend on the questionnaire as a main tool for collecting data and information, In order to deepen the answer to the following problems, we have asked the following questions: What are the knowledge management processes and the readiness of the General Authority for Taxation? What are the dimensions of knowledge management processes (knowledge acquisition, knowledge organization, transfer of knowledge) The study is based on the importance of research on this issue by identifying the extent to which knowledge management processes affect the achievement of tax excellence, especially since tax is considered one of the main resources of the state, especially the developing countrie

Seroprevalence study of IgG and IgM Antibodies to Toxoplasma, Rubella, Cytomegalovirus, Chlamydia trachomatis and Herpes simplex II in Pregnancy women in Babylon Province

In this work 180 blood samples was collected from pregnant women in Babylon province, Babylon maternity and children hospital from October/2008 to April/2009. It revealed that TORCH infections was; Cytomegalovirus formed (CMV) 57.2% followed by Toxoplasma gondii 55.5% Rubella 53.9%, Herpes simplex II 28.9% and Chlamydia trachomatis 24.4%. Seroprevalence of Toxoplasma, Rubella, CMV, Chlamydia trachomatis and Herpes IgM Antibodies according to various obstetric losses showed that Abortions happened in all causes with high percentage (Over than 30%) except Herpes infections (less than 6%), while congenital anomalies and premature delivery formed high ratio with some different in some cases. Neonatal deaths are very low under 1% except in CMV infections which formed 4.9%. Distribution of age with type of infection according IgM Antibodies to Toxoplasma, Rubella, CMV, Chlamydia trachomatis and Herpes simplex revealed that major age group for infection was between <20 to 40 years which formed more than two third of all infection cases. Residential distribution with type of infection according IgM Antibodies shows that most infection occurred in rural area (over than 50% in all agents) except in Herpes simplex infections which formed 82.7% in urban area. TORCH (Toxoplasma gondii, Rubella, Cytomegalovirus and Herpes simplex) infections with incidence of abortion in pregnant women in this study revealed that First trimester was the highest ratio of infection than other two trimesters

German Lexical Personality Factors: Relations with the HEXACO Model

We correlated the scales of the HEXACO Personality Inventory (HEXACO-PI) with adjective scale markers of factors previously obtained in indigenous lexical studies of personality structure in the German language. Self-ratings obtained from a sample of 323 German participants showed a pattern of strong convergent and weak discriminant correlations, supporting the content-based interpretation of the German lexical factors in terms of the HEXACO dimensions. Notably, convergent correlations were strong for both the broader and the narrower variants of the Honesty-Humility factor as observed in German lexical studies. Also, convergent correlations for HEXACO Openness to Experience were, as expected, stronger for German adjectives describing a creative and intellectual orientation than for German adjectives describing intellectual ability. Copyright © 2006 John Wiley & Sons, Ltd

Right ventricular dysfunction is a predictor of non-response and clinical outcome following cardiac resynchronization therapy

<p>Abstract</p> <p>Background</p> <p>Cardiac resynchronization therapy (CRT) is an established treatment in advanced heart failure (HF). However, an important subset does not derive a significant benefit. Despite an established predictive role in HF, the significance of right ventricular (RV) dysfunction in predicting clinical benefit from CRT remains unclear. We investigated the role of RV function, assessed by cardiovascular magnetic resonance (CMR), in predicting response to and major adverse clinical events in HF patients undergoing CRT.</p> <p>Methods</p> <p>Sixty consecutive patients were evaluated with CMR prior to CRT implantation in a tertiary cardiac centre. The primary end-point was a composite of death from any cause or unplanned hospitalization for a major cardiovascular event. The secondary end-point was response to therapy, defined as improvement in left ventricular ejection fraction ≥ 5% on echocardiography at one year.</p> <p>Results</p> <p>Eighteen patients (30%) met the primary end-point over a median follow-up period of 26 months, and 27 out of 56 patients (48%) were considered responders to CRT. On time-to-event analysis, only atrial fibrillation (HR 2.6, 95% CI 1.02-6.84, p = 0.047) and RV dysfunction, either by a reduced right ventricular ejection fraction-RVEF (HR 0.96, 95% CI 0.94-0.99, p = 0.006) or tricuspid annular plane systolic excursion-TAPSE (HR 0.88, 95% CI, 0.80-0.96, p = 0.006), were significant predictors of adverse events. On logistic regression analysis, preserved RVEF (OR 1.05, 95% CI 1.01-1.09, p = 0.01) and myocardial scar burden (OR 0.90, 95% CI 0.83-0.96, p = 0.004) were the sole independent predictors of response to CRT. Patients with marked RV dysfunction (RVEF < 30%) had a particularly low response rate (18.2%) to CRT.</p> <p>Conclusions</p> <p>Right ventricular function is an important predictor of both response to CRT and long-term clinical outcome. Routine assessment of the right ventricle should be considered in the evaluation of patients for CRT.</p

On the performance of online and offline green path establishment techniques

© 2015, Ruiz-Rivera et al. To date, significant effort has gone into designing green traffic engineering (TE) techniques that consolidate traffic onto the minimal number of links/switches/routers during off-peak periods. However, little works exist that aim to green Multi-Protocol Label Switching (MPLS) capable networks. Critically, no work has studied the performance of green label switched paths (LSPs) establishment methods in terms of energy savings and acceptance rates. Henceforth, we add to the current state-of-the-art by studying green online and offline (LSP) establishment methods. Online methods rely only on past and current LSP requests while offline ones act as a theoretical benchmark whereby they also have available to them future LSP requests. We introduce a novel metric that takes into account both energy savings and acceptance rates. We also identify a new simpler heuristic that minimizes energy use by routing source–destination demands over paths that contain established links and require the fewest number of new links. Our evaluation of two offline and four online LSP establishment methods over the Abilene and AT&T topologies with random LSP setup requests show that energy savings beyond 20 % are achievable with LSP acceptance rates above 90 %

Personalised external aortic root support (PEARS) in Marfan syndrome: Analysis of 1-9 year outcomes by intention-to-treat in a cohort of the first 30 consecutive patients to receive a novel tissue and valve-conserving procedure, compared with the published results of aortic root replacement

Objective: Among people with Marfan syndrome who have a typical aortic root aneurysm, dissection is a characteristic cause of premature death. To pre-empt Type A dissection, composite root replacement with a mechanical valve became the standard of care in the 1980s and 1990s. This is being superseded by valvesparing aortic root replacement to avoid lifelong anticoagulation. In 2004, a total root and valve-sparing procedure, personalised external aortic support, was introduced. We report here results among the first 30 recipients. Methods: From cross-sectional digital images, the patient's own aorta is modelled by computer aided design and a replica is made in thermoplastic by rapid prototyping. On this, a personalised support of a macroporous polymer mesh is manufactured. The mesh is positioned around the aorta, closely applied from the aortoventricular junction to beyond the brachiocephalic artery. The operation is performed with a beating heart and usually without cardiopulmonary bypass. Results: Between 2004 and 2011, 30 patients, median age 28 years (IQR 20-44) had this operation and have been prospectively followed for 1.4-8.8 years by February 2013. During a total of 133 patient-years there were no deaths or cerebrovascular, aortic or valve-related events. These early outcomes are better than published results for the more radical extirpative root replacement operations. Conclusions: The aortic valve, the root architecture, and the blood/endothelia interface are conserved. The perioperative burden is less and there has been freedom from aortic and valvular events. A prospective comparative study is planned