The correlation of microstructure and mechanical properties of in-situ Al-Mg2Si cast composite processed by equal channel angular pressing

In this paper, the effect of equal channel angular pressing (ECAP) on microstructure and mechanical properties of hypereutectic Al-20%Mg2Si and Al-15%Mg2Si, as well as hypoeutectic Al-10%Mg2Si composites has been investigated. After fabricating the composites by in-situ casting, the composites were processed using the ECAP process up to two passes at room temperature. Microstructural studies have been carried out using a field emission scanning electron microscopy equipped with an energy dispersive X-ray spectrometer. Mechanical properties were also documented using Vickers microhardness and shear punch tests. In the hypereutectic composites, a decrease in the average size of pro-eutectic Mg2Si (Mg2Sip) particles, breakages in eutectic networks, and lengthening of the Al (α) phase in direction of shear bands were observed after the ECAP process. For instance, the average size of Mg2Sip Particles in Al-20%Mg2Si composite reduced from 40 to 17 μm after 2 passes of ECAP. Furthermore, a uniform distribution of Mg2Sip particles was developed in the matrix. In hypoeutectic composite, the ECAP process caused a uniform distribution of eutectic Mg2Si (Mg2SiE) in the matrix that considered a favorable microstructure. Microhardness measurements and shear punch results showed an ascending trend after each pass of ECAP for all specimens. For example, microhardness and shear strength of Al-20%Mg2Si increased from 88 HV and 109 MPa to 119 HV and 249 MPa after two passes indicating 35% and 34% increments, respectively. Density and porosity calculations by Archimedes principle revealed that the density of the composites increased after two passes of ECAP due to the reduction of porosity

Effect of Equal Channel Angular Pressing (ECAP) on Wear Behavior of Al-7075 Alloy

AbstractEqual-channel angular pressing (ECAP) is an effective fabrication process for obtaining ultrafine grained materials. In order to investigate the effect of grain refinement during ECAP on wear properties of Al 7075 alloy, the specimens were pressed up to four passes by route BC at room temperature. Followed by ECAP, dry sliding wear tests have been conducted using a pin-on-disk machine under different loads of 10, 20 and 30N at a constant sliding speed of 0.23 ms-1. Microstructural observations were undertaken using transmission electron microscopy (TEM) and the surface of worn specimens was investigated by scanning electron microscopy (SEM). The effect of load and ECAP process on the mass loss, have been explained with respect to microstructure and wear mechanism. Comparison of wear resistance of specimens shows that by using ECAP process, wear resistance of the specimens increases considerably due to the formation of very fine grains during ECAP

Numerical modeling and estimation of renewable energy of tidal current in Khoore Musa

In this article, two three-dimensional hydrodynamic and numerical models, COHERENS and BOM are used to investigate the renewable tidal energy in Khoore Musa. Firstly, the effect of 6 tidal constituents on regional hydrodynamic is estimated in 10 sigma levels in vertical and 250 resolution. The results of both models are verified with field data recorded by Iranian National Institute for Oceanography. It is found that the outcomes of COHERENS are more reliable but calibration is required. Whereas the accuracy of calibrated hydrodynamic module of COHERENS is approved, the energy of tidal currents is calculated. In this study, the current energy module is developed and set as a supplementary module. Hourly averaging of current energy during one month indicated that the maximum value recorded was more than 0.65 MWh. The maximum depth-integrated energy of this area was about 5 MWh. The best and more advantageous area to extract energy is a strait in the Middle-Bar with density of more than 300

Interactive Visual Labelling versus Active Learning: An Experimental Comparison

Methods from supervised machine learning allow the classification of new data automatically and are tremendously helpful for data analysis. The quality of supervised maching learning depends not only on the type of algorithm used, but also on the quality of the labelled dataset used to train the classifier. Labelling instances in a training dataset is often done manually relying on selections and annotations by expert analysts, and is often a tedious and time-consuming process. Active learning algorithms can automatically determine a subset of data instances for which labels would provide useful input to the learning process. Interactive visual labelling techniques are a promising alternative, providing effective visual overviews from which an analyst can simultaneously explore data records and select items to a label. By putting the analyst in the loop, higher accuracy can be achieved in the resulting classifier. While initial results of interactive visual labelling techniques are promising in the sense that user labelling can improve supervised learning, many aspects of these techniques are still largely unexplored. This paper presents a study conducted using the mVis tool to compare three interactive visualisations, similarity map, scatterplot matrix (SPLOM), and parallel coordinates, with each other and with active learning for the purpose of labelling a multivariate dataset. The results show that all three interactive visual labelling techniques surpass active learning algorithms in terms of classifier accuracy, and that users subjectively prefer the similarity map over SPLOM and parallel coordinates for labelling. Users also employ different labelling strategies depending on the visualisation used

Investigating the effect of vitamin D vaginal suppository on sexual function among postmenopausal women: study protocol for a randomized controlled trial

Background: Menopause is associated with changes in sexual function which are partly due to vaginal atrophy in response to estrogen reduction. Estrogen administration temporarily reduces the symptoms of vaginal dryness, but long-term exposure to this drug is likely to be associated with serious complications. Considering the promising results of previous studies concerning the effect of vitamin D on vaginal dryness, the proposed study will investigate the effect of vitamin D vaginal suppository on the sexual function of postmenopausal women. Methods: In a randomized, controlled clinical trial, 105 postmenopausal women will be randomly assigned to three groups receiving vitamin D vaginal suppository, placebo vaginal suppository, or control (no intervention). Vitamin D vaginal suppositories contain 1000 units of vitamin D3. The timing of the use of vitamin D vaginal suppositories and placebo suppositories will be every night in the first 2 weeks, and every other night in the following 6 weeks (8 weeks in total). The primary outcome will be the sexual function of participants which will be assessed using the Female Sexual Function Index (FSFI) before and immediately after the intervention, and at 1 and 2 months after the end of the intervention. The side effects of these suppositories will be examined as a secondary consequence of the study. Data will be analyzed using SPSS software version 25. In the case of normal distribution of data, the mean score of sexual function will be compared between the groups using a repeated measurements ANOVA. If statistical analysis leads to significant results, the post-hoc test will be used to determine the differences between the groups. Comparison of demographic and fertility characteristics of the women will be carried out using statistical tests such as chi-squares and t-tests. A significance level of p [less than] .05 will be used for statistical analyses. Discussion: If vitamin D vaginal suppositories improve sexual function among premenopausal women with long-term effects and minimum side effects, the suppositories will be considered a safe complementary and alternative choice for alleviating sexual dysfunction among this group

Highly Efficient Formylation of Alcohols, Thiols and Aniline Derivatives by a Heterogeneous (HCOOH/SiO2) System under Microwave Irradiation and Solvent-free Conditions

A simple, rapid and efficient microwave-assisted procedure for the formylation of aniline derivatives and alcohols, using a heterogeneous (HCOOH/SiO2) system under solvent-free conditions is reported. The method is applied to a set of amines, alcohols and thiols and short reaction times (<10 min) with high yields are reported. This protocol introduces a practical and viable green technology of solvent-free and catalyst-free reactions.Keywords: Alcohols, anilines, SiO2, HCOOH, microwave irradiation, solvent-free condition

Adhesion Development and the Expression of Endothelial Nitric Oxide Synthase

Objective: This study was conducted to determine whether nitric oxide (NO), a potent vasodilator and inhibitor of thrombus formation, is involved in the formation and maintenance of adhesions. Methods: Skin, subcutaneous tissues, peritoneum and adhesions were collected from surgical patients and total RNA was isolated. Quantitative reverse transcription polymerase chain reaction (QRT-PCR) was performed to quantitate endothelial nitric oxide synthase (eNOS) and β-actin mRNA levels. Results: eNOS mRNA levels for skin, subcutaneous tissue, peritoneum and adhesions were ≤ 3.12 × 10(-4), ≤ 3.12 × 10(-4), 6.24 × 10(-4) and 2.5 × 10(-3) attomoles/μl, respectively. β-actin mRNA levels for all tissues were between 1.25 × 10(-1) and 6.25 × 10(-2) attomoles/μl. Conclusion: eNOS mRNA can be identified in tissue adhesions, and may therefore play a role in adhesion formation and maintenance

Macroautophagy in sporadic and the genetic form of Parkinson’s disease with the A53T a-synuclein mutation

The A53T mutation in the a-synuclein gene causes autosomal-dominant Lewy body Parkinson’s disease (PD). Cultured cell models have linked this mutation to increased cell macroautophagy, although evidence of enhanced macroautophagy in patients with this mutation has not been assessed. Objective: To determine whether macroautophagy is increased by the A53T a-synuclein gene mutation in PD patients and cell models. Methods: Formalin-fixed paraffin-embedded 10 μm-thick tissue sections from the substantia nigra and anterior cingulate cortex of two PD patients with the A53T a-synuclein gene mutation were compared with four sporadic PD cases and four controls obtained from the Sydney Brain Bank. Lewy bodies were isolated from frontal cortex of a case with late stage PD (recruited from South Australian Brain Bank). Immunohistochemistry was performed for a-synuclein and the macroautophagy markers autophagy-specific gene (ATG) 5, ATG6/Beclin1 and ATG8/LC3. SHSY5Y cells were transfected with wild type or A53T mutant a-synuclein plasmids and observable changes in macroautophagy marker protein levels assessed using Western blotting. Results: a-Synuclein immunoreactive neurites and dots were more numerous in patients with A53T mutations compared with late stage sporadic PD patients, and perinuclear cytoplasmic a-synuclein aggregates were observed in the a-synuclein A53T gene transfected SH-SY5Y cells compared to wild type transfections. All PD patients (with or without A53T mutations) had increased immunohistochemical evidence for macroautophagy compared with controls, and the levels of the ATG5 complex were equally increased in wild type and A53T a-synuclein gene transfected cells compared to controls. Conclusion: Despite increased a-synuclein accumulation with A53T mutations, macroautophagy is not increased above that observed in sporadic patients with PD or in cells transfected with wild type a-synuclein, suggesting that mutated a-synuclein protein is not removed by macroautophagy

The study of layering structure of outlfow from the Persian Gulf to Gulf of Oman and it's impact on propagation of sound with acoustic sources about outflow intrusion at spring

In this study, variations of field data such as temperature, salinity and sound of speed in horizontal and across transects of the Gulf of Oman were analyzed using CTD data acquired by international project, Joint Global Ocean Flux Study (JGOFS) during the spring of 1996. Results indicate that at all sections, at depths between 120 m to 276m in Gulf of Oman to 60 °E, finestructures were found; this indicates mixing with surrounding waters by thermohaline intrusions. These thermohaline intrusions caused temperature and salinity inversion that causes inversion of sound speed profile. Thickness inversion at the stations near the Strait of Hormuz is about 156 m and at stations far from the Strait of Hormuz (near the Oman of Sea) is about 80m. By previous studies, this outflow intrusion causes the internal waves in the Gulf of Oman. These results suggest that formation of intrusion depends on the intermittent outflow through the Strait of Hormuz. In this survey, high salinity water and high temperature water masses spread into the Persian Gulf at an intermediate level, in the Gulf of Oman. In this research, the acoustic propagation characteristics (transmission loss, amplitude of signal and travel time of signal) up, below and into, of the outflow intrusion were assessed based on the output of a range-dependant acoustic model and range independent acoustic model. In general, the occurrence of this thermohaline intrusion was found to alter the propagation characteristics