The contour method for residual stress determination applied to an AA6082-T6 friction stir butt weld

Residual stresses parallel to the welding direction on a cross-section of a 3 mm thick friction stir butt-welded aluminium alloy AA6082-T6 plate were determined using the contour method. This is a destructive relaxation based measurement technique capable of determining the full- eld residual stresses perpendicular to a plane of interest. A wire electro discharge machining cut was performed revealing the plane of interest. The residual stresses present before the straight cut lead to a deformed cutting plane. Then, a coordinate measuring machine was used to acquire the cutting plane shape of both plate halves after the cut. A data reduction scheme for noise and error elimination was used. The measured deformation was applied to a linear elastic nite elements model considering the real specimen geometry. A full contour map of longitudinal residual stresses on a weld cross section was determined in this way, revealing detailed information on the residual stress distribution in the inside of a friction stir weld, especially in the nugget zone. A typical M-shape, usually described for the residual stress distribution in friction stir welds, was found. The maximum residual stresses are below the yield strength of the material in the shoulder region and, outside of the welding region, low tensile and compressive residual stresses are responsible for the necessary stress equilibrium on the plane of interest. A comparison was made with the established incremental hole drilling technique on an equivalent plate for validation and good agreement of both techniques was obtained. The distribution, as well as the magnitude of the residual stresses measured by both techniques, is very similar, thus validating both the experimental and numerical procedures used for the contour method application, which is presented and discussed in the paper.The present work was partially funded by the project PTDC/EME-TME/66362/2006 and PhD scholarship SFRH / BD / 41061 / 2007 of the Portuguese Fundação para a Ciência e Tecnologia. Dr. P. Moreira acknowledges POPH - QREN-Tipologia 4.2 - Promotion of scientific employment funded by the ESF and MCTES. The help of José Fernando Rocha Almeida is also acknowledged

Influence of Concrete Compressive Strength on Transfer and Development Lengths of Prestressed Concrete

This research examines the relationship between concrete compressive strength and strand bond. The goal of this research was to develop an equation that relates strand bond to concrete compressive strength at strand release (approximately 1 day of age) and at 28 days of age, and those equations are presented in this investigation. Strand bond is assessed by measuring the transfer length and development length for prestressed beams cast in the laboratory. In the U.S., strand bond is predicted using transfer length and development length equations provided by the American Concrete Institute (ACI-318) Building Code and American Association of State and Highway Transportation Official (AASHTO) LRFD Bridge Design Specifications which were developed based on the 1950´s investigations. The equations provided by both ACI and AASHTO do not address concrete strength while equations, developed in this investigation, do account for the compressive strength of concrete at release and testing time. Although there has been much research conducted in this matter, this research provides a reliability data analysis relating to transfer and development lengths of prestressed concrete beams. Unlike many of the previous programs, this research includes strands of a known quality, the largest database of test specimens, and a variety of concrete mixtures and concrete strengths. This research concludes with the development of an analytical model to predict transfer length which includes concrete strength at release with fracture propagation around the strand

Salesforce control systems as direct antecedents of salesperson and sales unit performance: A literature review

[EN] The impact from sales control systems on individual and organizational effectiveness has been a major issue for scholars since these systems were conceptualized by Anderson and Oliver and Jaworski. Salesperson behavioral performance appears as an antecedent of outcome performance, and both are connected to sales unit effectiveness. This paper focuses on a deep literature review during the period 1983-2014, based on the control systems¿ typologies found, and summarizes the multiple evidences found, connecting this systems with the salesperson behavioral performance and the outcome performance ¿and between them-, and both individual results with the sales unit effectiveness, including its managerial implications. After the review of the 142 articles in the field, a cluster of four research directions are identified, namely: (1) the impact of the different variables and activities on the control systems and the performance levels, (2) the methodological variables, (3) the measures of the level control system or performance, and (4) the multisectorial, multicultural and multinational sales environment.Benet-Zepf, AT.; Marin-Garcia, JA.; Küster, I. (2017). Salesforce control systems as direct antecedents of salesperson and sales unit performance: A literature review. Business and Economics Journal. 8(1). doi:10.4172/2151-6219.1000281S2818

Relating air Pollution and Respiratory Diseases Occurrences.

info:eu-repo/semantics/publishedVersio

Bortezomib plus melphalan and prednisone in elderly untreated patients with multiple myeloma: updated time-to-events results and prognostic factors for time to progression

New treatment options offering enhanced activity in elderly, newly diagnosed patients with multiple myeloma are required. One strategy is to combine melphalan and prednisone with novel agents. We previously reported an 89% response rate, including 32% complete responses and 11% near complete responses, in our phase 1/2 study of bortezomib plus melphalan and prednisone (VMP) in 60 newly diagnosed multiple myeloma patients with a median age of 75 years. Here, we report updated time-to-events data and the impact of poor prognosis factors on outcome