Net shape HIPping of a Ni-superalloy: A study of the influence of an as-leached surface on mechanical properties

Hot Isostatic Pressing (HIP) is a net-shape powder metallurgy technique where powders densification is achieved through the application of high temperature and pressure at the same time. Powders are allocated into a hollow steel mold called capsule or canister which gives the final shape to the particles. This technique is particularly useful for manufacturing complex components made of materials which are extremely difficult to process via forging or casting. Thus, HIP is particularly indicated to handle superalloy powders such as Astroloy, which is the object of the following study. One of the most attractive peculiarities of HIP is the low material waste obtained since the overstock is limited to the layers immediately beneath the steel capsule. At the end of the HIP cycle, the canister is typically removed using an acid leaching bath which is responsible for the alteration of the outermost layers of the final product. Only a little number of research papers deal with the optimization of the removal of these layers; Consequently, manufacturers often apply a very conservative approach by eliminating more material than is actually needed with a final machining procedure. This paper aims to optimize this procedure by systematically assessing the total thickness of the altered layer of material deriving from the HIPping and leaching process together. To achieve this goal, a set of samples were prepared by removing progressively thicker layers of material and then they were bend tested. Finally, the recorded mechanical properties were compared with those obtained with the samples machined from the core material. One of the main findings is that the removal of 500 μm of material is enough to recover mechanical properties which are comparable with those observed in samples coming from the core. More specifically, by eliminating the first 100 μm material, all the corroded layer is removed, which results in an overall increase of all the mechanical properties except for ductility. This property strongly depends on the number of prior particle boundaries arising from the HIPping process itself. Thus, the correct amount of overstock material must include both these layers

Role of the chemical homogenization on the microstructural and mechanical evolution of prolonged heat-treated laser powder bed fused Inconel 625

Ni-based superalloy components for high-temperature applications rely on the long term stability of the microstructure and mechanical properties at service temperatures. Nowadays, the production of such types of components is frequently performed via Additive Manufacturing (AM) technologies. Nevertheless, few studies are dedicated to understanding the behavior of AM Ni-based superalloys upon prolonged exposure to high temperatures. This work aims at studying the effect of prolonged thermal exposures on the microstructure and mechanical properties of Inconel 625 processed by laser powder bed fusion. Thermal exposures within the range of 600 °C and 900 °C for 200 h were performed on this material. The as-built and solution annealed Inconel 625 conditions were selected. The solution annealed state implies a complete chemical homogenization, typically recommended for working at high temperatures, whereas the initial as-built state is characterized by segregations and fine dendritic structures. Upon the studied prolonged thermal exposures, the peculiar as-built microstructure formed a higher quantity of phases with smaller dimensions with respect to the solution annealed condition under thermal exposures. The smaller phases of the as-built state resulted in similar mechanical properties evolution under different temperatures. Differently, the prolonged heat-treated solution annealed conditions exhibited more marked mechanical properties variations due to coarser phases

In vitro efficacy of alphacypermethrin on the buffalo louse Haematopinus tuberculatus (Burmeister, 1839).

In Italy buffalo farms adopted intensive breeding techniques, however the high density of animals in intensive breeding favours the diffusion of ectoparasites, such as louse. The aim of this study was to determine the in vitro efficacy of the insecticide alphacypermethrin (ACYP) against the buffalo louse, Haematopinus tuberculatus. The study was performed by using louse collected from animals in a commercial buffalo farm located in the Campania region of Southern Italy. Lice (adults and nymphs) were collected from highly infested buffaloes. The ACYP was diluted with physiological solution to different concentrations: 1.5%, 0.75%, 0.37%. A volume of 600 μl of the diluted sample was spread evenly over a filter paper held in the lower half of Petri dish. Ten adult lice and ten nymphs were placed on the top of each filter paper disc. The control groups were treated with physiological solution. Seven replicates were used for each concentration. The louse vitality was assessed at different time intervals: 1, 2, 4, 8, 10, 15, 20, 30, 40, 50, 60 minutes, after every 10 min until 240 min or at the louse death. After 240 min the louse vitality was examined each 60 min until 540 min. In vitro bioassays revealed that the lousicidal efficacy of ACYP improved as the concentration and the exposure time increased. The results of this in vitro study confirm that ACYP at 1.5% concentration can also be used in buffalo for the control of lice, as already in use in cattle. Further field trials will need to be conducted to confirm the safety, the dosage and the in vivo parasitological efficacy of this drug on buffaloes

Manufacturing of PAV-ONE, a Permeator against Vacuum Mock-Up with Niobium Membrane

The Permeator Against Vacuum (PAV) is one of the proposed technologies for the Tritium Extraction System of the WCLL BB (Water-Cooled Lithium-Lead Breeding Blanket) of the EU DEMO reactor. In this paper, the manufacturing of the first PAV mock-up with a niobium membrane with a cylindrical configuration is presented. This work aimed to demonstrate the possibility of manufacturing a relevant-size PAV to be later tested in the TRIEX-II facility. The adopted prototypical solutions are described in detail, starting with the methodology developed to join the Nb tubes with a 10CrMo9-10 (A182 F22) plate. Dedicated manufacturing and welding procedures, based on vacuum brazing with a nickel-based brazing alloy, were developed to solve the problem. This new kind of brazing was first analyzed to check the morphology of the joint and then tested to check its capability to withstand the TRIEX-II operative conditions. In parallel, the compatibility with a lithium-lead environment was analyzed by exposing samples of niobium and 10CrMo9-10 (A335 P22) to a flow of the eutectic alloy at 500 °C up to 4000 h. Finally, the PAV mock-up was installed in the TRIEX-II facility

Major vascular traumas to the neck, upper limbs, and chest: Clinical presentation, diagnostic approach, and management strategies

Major vascular traumas to the neck, upper limbs, and chest may arise from penetrating and/or blunt mechanisms, resulting in a range of clinical scenarios. Lesions to the carotid arteries may also lead to neurologic complications, such as stroke. The increasing use of invasive arterial access for diagnostic and/or interventional purposes has increased the rate of iatrogenic injuries, which usually occur in older and hospitalized patients. Bleeding control and restoration of perfusion represent the two main goals of treatment for vascular traumatic lesions. Open surgery still represents the gold standard for most lesions, although endovascular approaches have increasingly emerged as feasible and effective options, particularly for management of subclavian and aortic injuries. In addition to advanced imaging (including ultrasound, contrast-enhanced cross-sectional imaging, and arteriography) and life support measures, multidisciplinary care is required, particularly in the setting of concomitant injuries to the bones, soft tissues, or other vital organs. Modern vascular surgeons should be familiar with the whole armamentarium of open and endovascular techniques needed to manage major vascular traumas safely and promptly

A checklist of chiggers from Brazil, including new records (Acari: Trombidiformes: Trombiculidae and leeuwenhoekiidae)

A checklist of the family Trombiculidae and Leeuwenhoekiidae is presented, containing 63 species in 30 genera of chiggers from 80 different hosts and 146 localities in Brazil. The type locality and depository are provided, including new locality and host records for the country

A contribution to the knowledge of Quadraseta brasiliensis Goff and Gettinger, 1989 (Trombidiformes: Trombiculidae), with description of the deutonymph instar

In the Neotropical region the genus Quadraseta Brennan, 1970, includes 14 species, with ectoparasitic habits during the larval stage. Quadraseta brasiliensis Goff and Gettinger, 1989, was described from larvae collected on the rodent Hylaeamys megacephalus (Fisher), cited as Oryzomys capito (Olfers). According to these authors, the holotype was deposited in the Museu de Zoologia da Universidade de São Paulo and the paratypes were deposited in three other collections: Bernice Pauahi Bishop Museum, Sam Noble Oklahoma Museum of Natural History and United States National Museum of Natural History, however, no type specimens were found in any of these museums. Here we redescribe the larva, describe the deutonymph instar obtained from field-collected larvae, and report new hosts and localities for this species in Brazil. In addition we provide sequences of the 18S ribosomal RNA gene for this species

The X-Ray Halo Scaling Relations of Supermassive Black Holes

We carry out a comprehensive Bayesian correlation analysis between hot halos and direct masses of supermassive black holes (SMBHs), by retrieving the X-ray plasma properties (temperature, luminosity, density, pressure, and masses) over galactic to cluster scales for 85 diverse systems. We find new key scalings, with the tightest relation being M-Tx, followed by M-Lx. The tighter scatter (down to 0.2 dex) and stronger correlation coefficient of all the X-ray halo scalings compared with the optical counterparts (as the M-se) suggest that plasma halos play a more central role than stars in tracing and growing SMBHs (especially those that are ultramassive). Moreover, M correlates better with the gas mass than dark matter mass. We show the important role of the environment, morphology, and relic galaxies/coronae, as well as the main departures from virialization/self-similarity via the optical/X-ray fundamental planes. We test the three major channels for SMBH growth: hot/Bondi-like models have inconsistent anticorrelation with X-ray halos and too low feeding; cosmological simulations find SMBH mergers as subdominant over most of cosmic time and too rare to induce a central-limit-theorem effect; the scalings are consistent with chaotic cold accretion, the rain of matter condensing out of the turbulent X-ray halos that sustains a long-term self-regulated feedback loop. The new correlations are major observational constraints for models of SMBH feeding/feedback in galaxies, groups, and clusters (e.g., to test cosmological hydrodynamical simulations), and enable the study of SMBHs not only through X-rays, but also via the Sunyaev-Zel dovich effect (Compton parameter), lensing (total masses), and cosmology (gas fractions)