Muography of different structures using muon scattering and absorption algorithms.

In recent decades, muon imaging has found a plethora of applications in many fields. This technique succeeds to infer the density distribution of big inaccessible structures where conventional techniques cannot be used. The requirements of different applications demand specific implementations of image reconstruction algorithms for either multiple scattering or absorption-transmission data analysis, as well as noise-suppression filters and muon momentum estimators. This paper presents successful results of image reconstruction techniques applied to simulated data of some representative applications. In addition to well-known reconstruction methods, a novel approach, the so-called µCT, is proposed for the inspection of spent nuclear fuel canisters. Results obtained based on both µCT and the maximum-likelihood expectation maximization reconstruction algorithms are presented.This article is part of the Theo Murphy meeting issue 'Cosmic-ray muography'.

INFN muon tomography demonstrator: past and recent results with an eye to near-future activities.

A short description of the muon tomography demonstrator at the INFN Laboratori Nazionali di Legnaro near Padua, Italy, is given and the principal achievements owing to the data collected at that experimental facility are presented. In particular, the feasibility studies for several applications based on the muon-tomographic technology, within national and European projects, are discussed. The experimental problems and the procedures used to improve the performance are underlined. In addition, new activities and the related detector optimization are illustrated.This article is part of the Theo Murphy meeting issue 'Cosmic-ray muography'.

Influence of severe plastic deformation on fatigue life applied by ultrasonic peening in welded pipe 316 Stainless Steel joints in corrosive environment.

Corrosive solutions have an enormous effect on fatigue life of components in refinery industry. Several post-processing solutions are proposed to improve the weld zone, which is affected by the corrosive solutions. Ultrasonic peening (UP) is developed to enhance the fatigue life, specifically in corrosive environments and corrosion resistance of the components. The enhancement mechanism of UP is based on severe plastic deformation and reduction of tensile residual stress in weld toe. In this research, the fatigue-corrosion life of welded 316 Stainless Steel (SS) pipe is enhanced through utilizing UP process with different diameters of strikers. Fatigue-corrosion life of the weld on 316 SS and 347 SS fillers, as experimental samples, is studied in corrosive environments. This study intends to shed more light on the influence of corrosion and strength in fatigue-corrosion life of the sample materials. Therefore, this article studies the microstructure and pitting corrosion of the samples at different zones. The experimental results showed enhancement of fatigue-corrosion life after applying UP. The results revealed that welding by using 316 SS filler and UP with striker diameter of 4 mm have the highest fatigue life in the simulated H2S corrosive environment.

Investigation of Ti-6Al-4V alloy acoustic softening.

High power ultrasonic vibration is widely used for improving manufacturing processes such as machining and metal forming. High frequency mechanical vibration affects material properties and friction forces in contacting surfaces. Flow stress reduction under superimposed ultrasonic vibration is called as acoustic softening. The amount of this parameter should be determined for ultrasonic assisted metal forming processes. For determination of this parameter for workhorse Ti-6Al-4V alloy, experimental setup was designed and fabricated. Then tensile test under longitudinal ultrasonic vibration was performed for different ultrasonic powers. Results show that ultrasonic vibration has considerable effect on plastic behavior of the alloy and decreases flow stress. Also, increasing ultrasonic power leads to higher acoustic softening. Yield stress reduction up to 9.52%, ultimate stress reduction up to 4.55% and elongation up to 13% were obtained at 340W ultrasonic power. After applying ultrasonic vibrations and its termination, hardness of specimens were measured in which increase up to 9% was observed.

Discrete regions of HIV-1 gp41 defined by syncytia-inhibiting affinity-purified human antibodies.

OBJECTIVE: Fine mapping of HIV-1 gp41 fusion-critical sites. DESIGN AND METHODS: Antibodies from human HIV-1-positive sera were affinity-purified on a panel of synthetic overlapping peptides spanning residues 526-682 of the extracellular portion of HIV-1 gp41. The syncytium-inhibiting capacity of the immunopurified antibodies and their differential reactivity on the synthetic peptides were tested. RESULTS: This approach enabled the identification of residues 583-591 (ARILAVERY), 595-599 (QQLLG), 603-609 (CSGKLIC) and 664-673 (ELLELDKWAS) as possibly involved in the fusion process. Reduction in the anti-ARILAVERY, anti-CSGKLIC and anti-ELLELDKWAS antibody titres and frequencies correlates with disease progression. Syncytia-inhibition capacity of sera did not correlate with the presence of high-titre antibodies reacting with any of the peptides tested, suggesting that most fusion-affecting antibodies are not directed towards gp41. CONCLUSIONS: This strategy may be relevant for understanding the contribution of anti-gp41 antibodies in protecting against the pathogenic effects of the virus and in the design of an effective env vaccine.