Hydrogen charging of carbon and low alloy steel by electrochemical methods

Atomic hydrogen can be the result of different processes like electroplating, chemical and electrochemical pickling treatments, in welding or by cathodic processes in corrosive fluids. Moreover, adsorption of atomic hydrogen can affect materials in contact with high pressure gaseous hydrogen. Once entered the material, atomic hydrogen interacts with the metal structure and may produce a "damage" of various forms, such as Hydrogen Induced Cracking (HIC), delayed fracture, blistering and hydrogen embrittlement. In particular, when H2S is present ("sour service"), metallic materials, such as carbon and low alloy steels, may suffer hydrogen damage and hydrogen embrittlement. Sour service materials must be used in compliance with international accepted standards, used worldwide in oil and gas activities, when fluids are classified as sour. The present study has been carried out in order to set up an electrochemical method to charge with hydrogen two typical pipeline materials, carbon and low alloy steels. The reason of the use of an electrochemical method is to avoid any critical conditions from the point of view of preparation, safety and disposal. Hydrogen content in the specimens was measured by two different methods: hot glycerol bath and Inert Gas Fusion (IGF) analysis. Hydrogen content in the specimens is about 0.6-2 ppm; mechanical performances were assessed by means of J integral tests: a pronounced decrease of fracture toughness was observed for H charged specimens.{GRAPHIACAL ABSTRACT

Adaptive Minimax Estimation over Sparse lq-Hulls

Given a dictionary of Mn initial estimates of the unknown true regression function, we aim to construct linearly aggregated estimators that target the best performance among all the linear combinations under a sparse q-norm (0 ≤ q ≤ 1) constraint on the linear coefficients. Besides identifying the optimal rates of aggregation for these `q-aggregation problems, our multi-directional (or universal) aggregation strategies by model mixing or model selection achieve the optimal rates simultaneously over the full range of 0 ≤ q ≤ 1 for general Mn and upper bound tn of the q-norm. Both random and fixed designs, with known or unknown error variance, are handled, and the `q-aggregations examined in this work cover major types of aggregation problems previously studied in the literature. Consequences on minimax-rate adaptive regression under `q-constrained true coefficients (0 ≤ q ≤ 1) are also provided

A Comprehensive Investigation on the Effects of Surface Finishing on the Resistance of Stainless Steel to Localized Corrosion

The present research investigates the influence of surface roughness imparted by cold surface finishing processes on the localized corrosion resistance of stainless steel. Five different alloys were studied: ferritic AISI 430, martensitic AISI 430F, austenitic AISI 303, AISI 304L, and AISI 316L. It was demonstrated that the grinding process, executed on previously cold drawn bars, leads to an improvement in corrosion resistance according to the results obtained with electrochemical tests, namely, potentiostatic and potentiodynamic tests in chloride-rich environments, the salt spray test, and long-term exposure in urban and marine atmospheres. This allowed us to establish a trend among the different alloys regarding the resistance to pitting corrosion, which was assessed according to pitting potentials, critical chloride contents, and pitting initiation time. All the tests confirmed that surface finishing, as well as alloy chemical composition, is an important factor in controlling the corrosion resistance of stainless steel

Maternal and Paternal Representations in Assisted Reproductive Technology and Spontaneous Conceiving Parents: A Longitudinal Study

Aim of this study was to investigate whether parental mental representations during pregnancy and after delivery differed between parents who conceived after Assisted Reproductive Treatments (ART) and spontaneous conceiving (SC) parents. Effects of specific ART variables (previous ART attempts, treatment type and cause of infertility) were also taken into account. Seventeen ART couples and 25 SC couples were recruited at Santa Maria Nuova Hospital (Reggio Emilia, Italy). At both 32 weeks of gestation (T1) and 3 months postpartum (T2) participants completed the Semantic Differential of the IRMAG, a self-report tool which measures specific domains of mental representations pertaining either individual (Child, Self-as-woman/man, and Partner) or parental (Self-as-parent, Own parent) characteristics. Results showed that ART parents had significantly more positive representations of the child compared to SC parents, while the scores at Partner dimension improved from T1 to T2 for SC parents only. With regards to ART history, scores at the Self-as-woman/man dimension were significantly less positive for ICSI than IVF parents and improved substantially from T1 to T2 only in case of mothers with previous ART attempts and of fathers at the first ART cycle. The representation of own parents increased from T1 to T2 in case of infertility diagnosis due to male factors, while a decrease emerged when infertility was due to female factors. Findings suggest the need to investigate parental mental representations after ART, in order to improve the understanding on the transition to parenthood of infertile couples and to target more specific intervention for parenting support

A Window into the Heterogeneity of Human Cerebrospinal Fluid Aβ Peptides

The initiating event in Alzheimer's disease (AD) is an imbalance in the production and clearance of amyloid beta (Aβ) peptides leading to the formation of neurotoxic brain Aβ assemblies. Cerebrospinal Fluid (CSF), which is a continuum of the brain, is an obvious source of markers reflecting central neuropathologic features of brain diseases. In this review, we provide an overview and update on our current understanding of the pathobiology of human CSF Aβ peptides. Specifically, we focused our attention on the heterogeneity of the CSF Aβ world discussing (1) basic research studies and what has been translated to clinical practice, (2) monomers and other soluble circulating Aβ assemblies, and (3) communication modes for Aβ peptides and their microenvironment targets. Finally, we suggest that Aβ peptides as well as other key signals in the central nervous system (CNS), mainly involved in learning and hence plasticity, may have a double-edged sword action on neuron survival and function

Recent Advances in the Use of Green Corrosion Inhibitors to Prevent Chloride-Induced Corrosion in Reinforced Concrete

Inhibitors for the prevention of corrosion in reinforced concrete are chemical substances able to reduce carbon steel reinforcements corrosion without altering the overall properties of concrete. Today, many commercially available substances have a negative impact on human safety during either the inhibitor synthesis, their handling or application in field. Green corrosion inhibitors are nontoxic, biodegradable and environmentally biocompatible substances. They are generally made of extracts from natural plants or waste, which are abundantly available in several countries. The majority of green inhibitor molecules usually contain multiple bonds, aromatic rings, polar functional groups and electronegative atoms as P, N, S or O; the latter are able to coordinate with metal cations to form protective layers on the metallic surface of the reinforcements, so as to inhibit the development (initiation and/or propagation) of the corrosion process. In this review, the most recent achievements on the study and investigation of green corrosion inhibitors for concrete structures are presented and discussed. Inhibitors are classified based on their nature and inhibition mechanism. The inhibition effectiveness of the substances is compared with the well-established effective nitrite-based inhibitor, distinguishing between accelerated and long-term tests. Based on the available data, a summary of corrosion inhibitors efficiency is reported

Interprofessional collaboration between different health care professions in emilia romagna

Background and aim of the work: Interprofessional collaboration in the healthcare sector contributes to the delivery of high quality and safe services to patients across different subdivisions of the healthcare system which is faced with constant challenges. The international literature offers a plethora of tools for assessing the collaboration between health workers, but only a few of these have been validated in the Italian language. One that has undergone such validation is the interprofessional collaboration (IPC) scale, which measures the perception of collaboration among health professionals. An advantage of this scale is that is addresses all workers within the system, and is not limited to specific professions. The aim of the present study was to apply the validated Italian version of the IPC scale, to a context different to the one used for its validation, to measure the level of collaboration between different health care workers. Method: A questionnaire-based study was conducted on a sample consisting of 329 health professionals working at Azienda USL-IRCCS in Reggio Emilia. The categorical and continuous variables were analysed using descriptive statistics (frequen-cies, percentages and standard deviations). Results: The IPC scale showed physicians to express the highest level of collaboration with other professionals, in line with the results of other studies in the literature. The values calculated for the factors “accommodation” and “communication” were higher than for “isolation”, de-picting a good level collaboration. The only case in which the isolation factor, which describes an absence of collaboration, was equal to the other two factors was in relation to the evaluation of midwives by nursing aides/orderlies. Conclusions: In conclusion, the Italian version of the IPC scale provides a useful instrument for measuring interprofessional collaboration between workers in the healthcare sector. In the present study, it revealed a satisfactory level of collaboration between health professionals in an organization located in Emilia Romagna, Italy. (www.actabiomedica.it)

Contourite terraces along the Argentine continental margin : morphosedimentary and oceanographic implications

Un enorme Sistema Deposicional Contornítico, compuesto mediante rasgos deposicionales y erosivos, ha sido caracterizado en el margen continental Argentino. El presente trabajo se centra en los rasgos erosivos contorníticos y en concreto en uno de ellos: las terrazas contorníticas. Se identifican a lo largo del talud continental, y a diferentes profundidades, un conjunto de terrazas con una muy buena continuidad lateral. Esta terrazas son elementos morfológicos sub-horizontales sobre el actual fondo submarino desarrolladas durantes sucesivas fases constructivas (deposicionales) y erosivas mediante la acción de las masas de agua antárticas que interaccionan con el talud continental. Regionalmente la ubicación de las terrazas se correlaciona con la posición de las interfases entre las principales masas de agua. La presencia de las terrazas contorníticas implica cambios muy significativos en el perfil morfológico del talud, generando un perfil muy diferente al definido en los modelos conceptuales de los taludes para los márgenes continentalesA significant Contourite Depositional System on the slope of the Argentine margin was characterised, where several depositional and erosive features are well developed. This work is focused on one of these erosive features: the contourite terraces. A set of terraces with good lateral continuity has been described at different depths along the slope. They are sub-horizontal morphologic elements identified at the present sea-floor, which have developed over time in constructional (depositional) and erosive phases caused by the interaction of Antarctic water masses with the seafloor. Their location can be correlated with the main interfaces of water masses. Contourite terraces occurrence has conditioned a remark change in the slope morphologic profile very different to those defined in the conceptual models for continental margin