Fatigue assessment of high‐frequency mechanical impact (HFMI)‐treated welded joints subjected to high mean stresses and spectrum loading

The fatigue strength of welded joints can be improved with various post‐weld treatment methods. High‐frequency mechanical impact treatment is a residual stress modification technique that creates compressive residual stresses at the weld toe. However, these beneficial residual stresses may relax under certain loading conditions. In this paper, previously published fatigue data for butt and fillet welded joints subjected to high stress ratios and variable amplitude cyclic stresses were evaluated in relation to the current International Institute of Welding (IIW) recommendations on fatigue strength improvement and a proposed IIW design guideline for high‐frequency mechanical impact‐treated welded joints. The evaluation showed that the current IIW recommendations resulted in both non‐conservative and overly conservative fatigue strength estimations depending on the applied stress level, whereas the proposed fatigue assessment guideline fitted the current data well.     

Development of Data Sheets for Statistical Evaluation of Fatigue Data

  Instructions were developed for statistical analysis of the laboratory fatigue data step by step. Practical cases for solving several questions raised in the treatment of test data, which involved estimation of necessary sample size, verification of the statistical equivalence of the collated sets of data, and determination of characteristic curves in different cases, were given by using the methods and formulae in the document IIW XIII 2138 06 (best practice guide on the statistical analysis of fatigue data) as a demonstration of various statistical methods of developing a sound procedure for creating reliable calculation rules for the fatigue analysis.     

Michael J. Mahoney: A retrospective.

Michael Mahoney, who made seminal contributions not only to the Society for the Exploration of Psychotherapy Integration (SEPI) but also to the entire field of psychotherapy, died a tragic death at the age of 60 on May 31, 2006. He published more than 250 scholarly articles and chapters, authored and edited 19 books (one of which was awarded a Citation Classic by the Science Citation Index), edited 4 journals, and served on 23 editorial boards plus numerous guest editorships and advisory boards. His research spanned a tremendous breadth without sacrificing depth. Primarily, however, he inquired into development across the life course, including but not limited to psychotherapy. Initially trained as a behaviorist, he played a significant role in the cognitive revolution in psychology; he was also a leading figure in constructivist psychotherapies. He was a Fellow of the World Academy of Art and Science, as well as a Fellow of the American Association for the Advancement of Science. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Shear decohesion of clamped abraded steel interfaces reinforced with epoxy adhesive

This paper presents an experimental assessment of quasi-static shear strength of the combined mechanically clamped and epoxy adhesive reinforced steel interfaces. The effect of the surface roughness and clamping load on the combined interfacial decohesion and slipping is investigated. The maximum shear strength of the adhesive reinforced specimens with fine ground, coarse ground and grit blasted contact surface finishes is reported with comparison to the results of the identical non-reinforced specimens. Results have been assessed both in terms of calculated fracture energy and interface decohesion. The bonded interfaces with grit blasted finish showed considerably higher maximum shear stresses as compared to the identical ground cases. The shear strength contributions of strong clamping and reinforcing conformed well to the principle of superposition for all experimented interface types.     

THREE-DIMENSIONAL NUMERICAL MODELING OF HEAT AND MASS TRANSFER IN A CERAMIC OXYGEN GENERATOR (COG)

A three-dimensional numerical model has been developed to simulate the conjugate heat transfer and the separation of oxygen from air in a single-cell ceramic oxygen generator (COG). Attention is focussed on the temperature distribution in the brittle ceramic electrolyte as a result of heat generated from electrochemical reactions and the resistance to current flow. Investigations conducted to determine the influence on the thermal behaviour of the electrolyte with the presence of metallic current collectors and gas distributors in the model will also be summarised.     

Modelling and fatigue life assessment of complex structures

This paper presents some of the motivations and main conclusions from a series of joint Nordic research initiatives in which an integrated research approach to the development of future generations of advanced fabricated structures have been employed. The integrated research approach includes coordinated efforts in several key technologies: high‐speed welding processes, high strength materials, cost‐effective NDE, post‐weld treatments and FE‐based design assessment tools. Traditionally, fatigue assessment methods for welded structures have been developed based on small‐scale test specimens and verification studies for large structures are rarely published. Applications on complex structures have led to several new assessment concepts and areas for future work. A modified structural stress method that proposes a multi‐linear stress distribution through the plate thickness is introduced. Also, a crack growth assessment method in which the constraint equations of a sub‐model are linked to the global model is presented. Both these new methods are promising for complex structures. The crucial role of boundary conditions for complex structures is highlighted as is the future challenge of understanding and making use of the residual stress state for welded structures.     

Spectrophotometric and atomic absorption spectrometric determination of ramipril and perindopril through ternary complex formation with eosin and Cu(II)

Two sensitive, spectrophotometric and atomic absorption spectrometric procedures are developed for the determination of ramipril and perindopril. Both methods are based on the formation of a ternary complex, extractable with chloroform, between copper(II), eosin and the two cited drugs. Spectrophotometrically under the optimum condition, the ternary complexes showed an absorption maximum at 535 nm, with apparent molar absorptivities of 6.55 and 4.00 x 10(3) mol(-1) x cm(-1) and Sandell's sensitivities of 5.80 x 10(-2) and 1.04 x 10(-1) microg x cm(-2) for perindopril and ramipril, respectively. The solution of ternary complex obeyed Beer's law in concentration ranges 10-60 and 20-100 microg x ml(-1) for perindopril and ramipril, respectively. The proposed method was applied to the determination of the two cited drugs in pharmaceutical tablets. The atomic absorption spectrometric method, directly through the quantitative determination of copper content of the organic extract of the complex, was also investigated for the purpose of enhancing the sensitivity of the determination. The spectrophotometric and atomic absorption spectrometric procedures hold their accuracy and precision well when applied to the determination of ramipril and perindopril dosage forms.     

Peripheral synapses at identified mechanosensory neurons in spiders: three-dimensional reconstruction and GABA immunocytochemistry

The mechanosensory organs of arachnids receive diverse peripheral inputs. Little is known about the origin, distribution, and function of these chemical synapses, which we examined in lyriform slit sense organ VS-3 of the spider Cupiennius salei. The cuticular slits of this organ are each associated with two large bipolar mechanosensory neurons with different adaptation rates. With intracellular recording, we have now been able to correlate directly the staining intensity of a neuron for acetylcholinesterase with its adaptation rate, thus allowing us simply to stain a neuron to identify its functional type. All rapidly adapting neurons stain more heavily than slowly adapting neurons. Immunostaining of whole-mount preparations reveals GABA-like immunoreactive fibers forming numerous varicosities at the surface of all sensory neurons in VS-3; peripheral GABA-like immunoreactive somata are lacking. Sectioning the leg nerve procures rapid degeneration of most fiber profiles, confirming that the fibers are efferent. Punctate synapsin-like immunoreactivity colocalizes to these varicosities, although some synapsin-like immunoreactive puncta are GABA-immunonegative. Fibers with similar immunoreactivities are also associated with trichobothria, tactile hairs, internal joint receptors, i.e. other types of spider mechanosensory organs. In organ VS-3, immunoreactivity is most dense across the initial axon segment. The exact distribution of peripheral synapses was reconstructed from a 10-microm-long electron micrograph series of the dendritic, somatic, and initial axon regions of acetylcholinesterase-stained VS-3 neurons. These reveal a pattern similar to that of the synapsin-like immunoreactivity. Two different types of synapse were distinguished on the basis of their presynaptic vesicle populations. Many peripheral synapses thus appear to derive from efferent GABA-like immunoreactive fibers and probably provide centrifugal inhibitory control of primary mechanosensory activities.