Heat generation during plunge stage in friction stir welding

This paper deals with the heat generation in the Al alloy Al2024-T3 plate under different rotating speeds and plunge speeds during the plunge stage of friction stir welding. A 3-D finite element model is developed in the commercial code ABAQUS/Explicit using the arbitrary Lagrangian-Eulerian formulation, the Johnson- Cook material law, and Coulomb's Law of friction. The heat generation in friction stir welding can be divided into two parts: frictional heat generated by the tool and heat generated by material deformation near the pin and the tool shoulder region. Numerical results obtained in this work indicate a more prominent influence from the friction-generated heat. The slip rate of the tool relative to the workpiece material is related to this portion of heat. The material velocity, on the other hand, is related to the heat generated by plastic deformation. Increasing the plunging speed of the tool decreases the friction-generated heat and increases the amount of deformation-generated heat, while increasing the tool rotating speed has the opposite influence on both heat portions. Numerical results are compared with the experimental ones, in order to validate the numerical model, and a good agreement is obtained

Cytogenetic alterations in rheumatoid arthritis patients treated with methotrexate and dry olive leaf extract

Oxidative stress and inflammation are DNA instability factors for rheumatoid arthritis (RA) patients. The aims of this study were to evaluate cytogenetic alterations in Peripheral Blood Lymphocytes (PBL) in two groups of RA patients: the early and the long-term RA group; and to examine potential of concomitant treatment with Methotrexate (MTX) and Dry olive leaf extract (DOLE) against cytogenetic damage in RA patients after a 3-weeks treatment. A total of 32 RA patients and 10 healthy individuals were included. RA patients were equally divided into four groups: two groups with early phase RA (one treated with MTX alone, the other in combination with DOLE); and two long-term phase RA groups (group with active disease and group with low disease activity)-both treated with MTX and DOLE combination. PBL cultures were screened for chromosome aberrations and micronuclei frequencies. Significantly increased frequencies of micronuclei were shown in active phase RA disease (both early and long-term) but not in the group with low disease activity, as compared to controls. Chromosome aberrations were detected for all 4 RA groups. The highest frequencies of micronuclei and chromosome aberrations were found in the long-term active RA group. After 3 weeks-treatment, there were no significant decrease of the micronuclei frequencies compared to baseline, although they were reduced in all RA groups, except for the group with the long-term active disease. High level of cytogenetic damage in RA patients was concordant with duration and activity of the RA disease. At 3 weeks of therapy, neither the combined treatment (MTX+DOLE), nor MTX alone did not affect the frequency of micronuclei formation

Prevalence of spondyloarthritis and its subtypes - are they really comparable?

Introduction/Objective. Increasing spondyloarthritis (SpA) prevalence in the last several decades cannot be attributed to disease manifestations alone. The objective of this paper is to review the prevalence of SpA and its subtypes: ankylosing spondylitis (AS), psoriatic arthritis (PsA), reactive arthritis (ReA), SpA related to inflammatory bowel disease (IBD) and undifferentiated SpA (UnSpA). Methods. MEDLINE literature search was done via PubMed, Google Scholar, and Embase databases, using terms for spondyloarthritis, and prevalence, with an additional hand searching. Results. As compared with southern European countries, northern European countries (Scotland, Sweden, France) showed lower SpA prevalence rates (0.21–0.45% vs. 1.06% and 1.35% in Italy and Turkey, respectively). The lowest world SpA prevalence was in African and Southeast Asian countries (0–0.19%), and the highest was in Alaska (2.5%). The widest variability in PsA prevalence was in Europe (northern 0.02–0.19%, southern 0.42%). The lowest world PsA prevalence was in Japan (0.001%), followed by China (0.01–0.10%). The European ReA prevalence ranged from 0.04% in Greece to 0.10% in Serbia and Germany, and the European UnSpA prevalence varied from 0.02% in Serbia to 0.67% in Germany; the highest world UnSpA prevalence was in Lebanon (3.4%). Studies aimed at estimating the SpA prevalence differed in sampling strategy and confirmation criteria, different cutoffs for age groups inclusion, presentation of standardized or row results, etc. Conclusion. Variation in the SpA prevalence cannot be attributed to genetic or geographic distribution only. Differences in methodology of studies add to the diversification, described more in-depth in this review

Novel ternary Ni-Co-Mo based ionic activator for efficient alkaline water electrolysis

In this manuscript we have presented the results of the use of ternary ionic activator in the alkaline water electrolysis. Novel Ni-Co-Mo based ionic activator was added in-situ to standard electrolyte. Energy consumption of the alkaline electrolyzer was determined at different current densities and elevated temperatures. Energy saving was higher at higher temperatures and higher operating current densities. Results showed that the reduction in energy consumption using Ni-Co-Mo based ionic activator was about 17%, compared to standard 6 M KOH. SEM morphology investigation proved the deposition of nickel, cobalt and molybdenum species on the cathode, greatly increasing the active surface area. UV/VIS spectroscopy was used to monitor changes in the electrolyte composition during the electrolytic process, and results show the decrease in the ionic activator concentration in the 6 M KOH. Our experiments point out a strong possibility of the usage of these ternary ionic activators in industrial alkaline electrolyzers. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved