Pitting Corrosion of 410 Stainless Steel in HCl Solutions

410 stainless steel (SS) is a material used in HCl services, such as distillation column trays in oil refineries. Unlike other alloys, however, the oil refining industry lacks a good reference for the corrosion rate of 410 SS at the varying HCl concentrations and temperatures the material might experience as trays in crude unit distillation columns. The goal of this project is to fill that knowledge gap. The corrosion behavior of 410 SS in HCl environments of pH 0.50, 1.25, 2.25, 3.25, and 4.25 at temperatures of 38, 52, 79, and 93°C was investigated using several methods. Cyclic potentiodynamic polarization experiments were performed to determine the pitting potential, repassivation potential, and open circuit potential of 410 SS in different environments, temperature ramping experiments were performed to determine the critical temperature of 410 SS at various HCl concentrations, and exposure experiments were performed to observe pitting behavior over several days. The results are summarized in a graph with temperature and pH axis that groups environments into metastable pitting, activing pitting, and uniform corrosion of 410 SS. This easy to use graph will aid industry in material selection choices

An extreme case of plant-insect co-diversification: figs and fig-pollinating wasps

It is thought that speciation in phytophagous insects is often due to colonization of novel host plants, because radiations of plant and insect lineages are typically asynchronous. Recent phylogenetic comparisons have supported this model of diversification for both insect herbivores and specialized pollinators. An exceptional case where contemporaneous plant insect diversification might be expected is the obligate mutualism between fig trees (Ficus species, Moraceae) and their pollinating wasps (Agaonidae, Hymenoptera). The ubiquity and ecological significance of this mutualism in tropical and subtropical ecosystems has long intrigued biologists, but the systematic challenge posed by >750 interacting species pairs has hindered progress toward understanding its evolutionary history. In particular, taxon sampling and analytical tools have been insufficient for large-scale co-phylogenetic analyses. Here, we sampled nearly 200 interacting pairs of fig and wasp species from across the globe. Two supermatrices were assembled: on average, wasps had sequences from 77% of six genes (5.6kb), figs had sequences from 60% of five genes (5.5 kb), and overall 850 new DNA sequences were generated for this study. We also developed a new analytical tool, Jane 2, for event-based phylogenetic reconciliation analysis of very large data sets. Separate Bayesian phylogenetic analyses for figs and fig wasps under relaxed molecular clock assumptions indicate Cretaceous diversification of crown groups and contemporaneous divergence for nearly half of all fig and pollinator lineages. Event-based co-phylogenetic analyses further support the co-diversification hypothesis. Biogeographic analyses indicate that the presentday distribution of fig and pollinator lineages is consistent with an Eurasian origin and subsequent dispersal, rather than with Gondwanan vicariance. Overall, our findings indicate that the fig-pollinator mutualism represents an extreme case among plant-insect interactions of coordinated dispersal and long-term co-diversification

Taxonomy based on science is necessary for global conservation

Peer reviewe

Psychological and socio-demographic data contributing to the resilience of Holocaust Survivors.

We provide a within group study of 65 Former Hidden Children (FHC; i.e. Jewish youths who spent World War II in various hideaway shelters across Nazi-occupied Europe) evaluated by the Hopkins Symptom Check List, the Sense of Coherence Scale, the Resilience Scale for Adults, which has a six factors solution, and a socio-demographic questionnaire. The aim of the present paper is to address the sensitization model of resilience (consisting in a reduction of resistance to additional stress due to previous exposure to trauma) and to identify the family, psychological and socio-demographic characteristics that predict resilience among a group of FHC. In multiple regression analyses, and in accordance with the sensitization model, the number of post-war traumas negatively predicts the resilience. Moreover, the sense of coherence and the number of children positively predict it. Our data also confirm that the resilience construct is multi-factorial, five domains of resilience being influenced by psychological or socio-demographic characteristic while a sixth one remains unaltered. Future studies of resilience among survivors of massive trauma occurring during childhood should take these variables into account when attempting to test models of resilience. Therapeutic implications are discussed, limitations are considered and further investigations are proposed.SCOPUS: ar.jinfo:eu-repo/semantics/publishe