Effects of pin diameter and number of cycles on microstructure and tensile properties of friction stir fabricated AA1050-Al2O3 nanocomposite

Nanocomposites of Al-Al2O3 are fabricated by means of friction stir processing (FSP). Effects of pin diameter and number of FSP cycles on tensile properties of the nanocomposites are investigated and the variations are correlated to the evolution of microstructure and distribution of nanoparticles in addition to agglomeration of Al2O3 nanoparticles. Investigation of agglomeration has been considered as an indirect indication for efficiency of the process for distribution of nanoparticles. The ductility of the nanocomposite is found to improve due to grain refinement during FSP. However, the ductility is likely to degrade if Al2O3 particles agglomerate and form coarse particles. The composite fabricated using the 6-mm pin indicates the maximum ductility which is attributed to formation of fine grain structure and efficient distribution of nanoparticles in the composite. Although, the grain structure in the composite fabricated using 8-mm pin is well refined, this sample shows significantly lower ductility with respect to the other samples. This was attributed to formation of coarse agglomerated particles. The second pass of FSP is found to slightly improve ductility and strength in composites fabricated using 4- and 6-mm pins but enforce significant improvements in the one with 8-mm pin. This is indeed because the second pass results in significant change in the distribution of nanoparticles or agglomerated particles in the latter case and negligible in the former ones. Grain structure and nanoparticle distribution and agglomeration can all affect the fracture surface of the tensile specimens of the fabricated nanocomposite to be ductile or brittle

Sensitivity to hydrogen induced cracking, and corrosion performance of an API X65 pipeline steel in H2S containing environment: influence of heat treatment and its subsequent microstructural changes

In this investigation, the effect of microstructural changes and phase equilibria on corrosion behavior and hydrogen induced cracking (HIC) sensitivity of an API X65 pipeline steel was studied. For this purpose, heat treatment was performed at 850 °C, 950 °C, 1050 °C and 1150 °C to engineer the desired microstructure of this pipeline steel. Then, the microstructural evolution was performed by optical microscopy, and Field Emission Scanning Electron Microscopy (FE-SEM) equipped with Energy Dispersive X-Ray Spectroscopy (EDS). Corrosion properties were evaluated in H2S environment by open circuit potential (OCP), Potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS). As well, HIC sensitivity of the API X65 pipeline steel was assessed by hydrogen charging of the cathode and immediately conducting the tensile test. Microscopy analyses showed that the microstructure of the steel is ferritic-pearlitic together with the islands of martensite/austenite constituents. Increasing the heat treatment temperature reduced the amount of pearlite and increased ferrite grain size. It also stabilized the ferrite content. Corrosion results indicated that no active layer was formed on the surface of this pipeline steel. Also, increasing the heat treatment temperature increased the corrosion resistance and reduced sensitivity to micro-galvanic localized corrosion. As well, results suggested that the sensitivity to HIC in the API X65 pipeline was substantially increased with increasing the amount of pearlite and reducing the amount of ferrite; i.e. at lower heat treatment temperature.publishedVersio

Comparing the Expectations of Financial Reporting Preparers and Users of Integrated Financial Reporting

Integrated financial reporting provides crucial information about an organization's strategy, direction, performance, and future outlook encompassing business, social, and environmental performance within its operational context. It also promotes a coherent and effective approach to corporate reporting. This research aims to compare the expectations of integrated financial reporting producers and users. Data analysis using SPSS software and statistical tests, including "Kolmogrove-smirnov", "Yoman-whitney" and "Friedman" has shown significant differences between the opinions of users and financial report preparers regarding report components, innovative practices, targeted investments, rewards and benefits, risk management, governance structure, and balanced scorecard. However, the comparison of expectations has shown no significant difference between the expectations of report providers and users regarding providing reports on mutual communication, compliance with legal and ethical standards, user’s engagement, and the reporting of financial status and sustainability of financial services.IntroductionAn integrated report should provide insight into the nature and quality of an organization's relationships with its key stakeholders. According to the International Integrated Reporting Council (IIRC), one of the guiding principles which underpin the preparation of integrated reports is the formation of effective stakeholder relationships. However, several challenges are also identified. These challenges include difficulties in determining what information is material and should, therefore, be included in an integrated report. This paper contributes to the ongoing debate on the quality and utility of integrated reporting by exploring the possibility that a perception gap has emerged, which affects the perceived relevance of integrated reporting. this paper makes an important contribution to the prior literature on integrated reporting by introducing the idea of a perception gap and offering one of the initial accounts of stakeholders’ perspectives on companies’ integrated reports. This will shed light on where companies can improve their integrated reports and inform the development of additional guidance by standard-setters and regulators.MethodologyThe study's statistical population comprises two groups: report producers and users. This includes auditors from the audit organizations and audit institutions, members of the Society of Official Accountants of Iran, as well as board directors and managers of companies listed on the Tehran Stock Exchange during the year 2022. The sampling method employed in this research is available sampling. This research is classified as a descriptive-survey study with an applied approach. The identified themes are incorporated into a Likert scale questionnaire. Lastly, the collected data were analyzed using SPSS software and relevant statistical tests.FindingsBased on the findings, there is a gap between auditors' and users' perspectives in terms of reporting and identifying innovative perspectives, targeted investments, rewards and benefits, risk management, governance structure, and balanced scorecard. Conversely, no significant gap is anticipated between the perspectives of producers and users in terms of mutual communication, compliance with legal and ethical standards, streamlining financial operations, user communication, as well as reporting financial status and corporate sustainability.Conclusion and discussionIn line with the examination of expectations between providers and stakeholders concerning the disclosure of integrated reporting components, the results of hypothesis testing indicate that, except for reporting and identifying innovative perspectives, targeted investments, rewards and benefits, risk management, governance structure, and balanced evaluation card, there is no significant expectation gap between beneficiaries and providers. In fact, the results indicate that users of integrated reports seek additional information on matters such as the competence and performance of those responsible for governance and how management has handled risk to ensure financial sustainability and prevent financial crises. They prioritize these aspects over the disclosure of information about social and environmental issues.Finally, the results of this study highlight several areas for future research. It would be valuable to investigate whether a perception gap exists in other industries and to identify the factors contributing to changes in the perception gap. More work also needs to be done to understand the determinants of the perception gap. This paper is based on the assumption that user sophistication affects the perceived importance of disclosures found in integrated reports. Cultural variables, the nature of the corporate governance system and the extent to which companies are able to manage perceptions are additional variables which need to be taken into account in order to define the dimensions of the perception gap in an integrated reporting context more accurately and inform policymakers and standard setters

The Effect of Melissa officinalis Hydro Alcoholic Extract on Liver Enzymes, Markers of Kidney Function and Testosterone in Lead Poisoned Rats

Background: Lead, one of the most important environmental pollutants, can induce a broad range of physiological dysfunction. The aim of this study was to investigate the protective effect of the Melissa officinalis plant extract on biomarkers of liver and kidney function as well as serum testosterone concentration in lead-exposed male rats. Methods: We used 40 Wistar rats and divided them into 5 groups. The control group received saline (1 mL/kg) by gastric gavage and 30 minutes later received saline (1 mL/kg) through i.p injection. The lead group received saline (1 mL/kg) by gastric gavage and 30 minutes later received i.p injection of lead acetate (20 mg/kg). The treatment groups received different doses of M. officinalis alcoholic extract (20, 100, and 500 mg/kg, respectively) by gastric gavage and 30 min later received i.p injection of lead acetate (20 mg/kg). The rats were treated for 5 days and then twenty -four hours after the last injection, blood samples were collected for the measurement of urea, creatinine, uric acid, alanine transaminase (ALT), alkaline phosphatase (ALP), aspartate transaminase (AST) and testosterone. Data analysis was performed through SPSS (version 16). Results: Melissa extract (100 mg/kg) significantly reduced liver enzymes and kidney function markers when compared to the lead group. Treatment with Melissa extract (100 mg/kg and 500 mg/kg) significantly increased serum testosterone concentration compared to the lead group. Conclusion: The biochemical results of this study showed that M. officinalis may be beneficial in lead-induced liver and kidney dysfunction

The relationship between basal and luminal cytokeratins with histopathologic characteristics of canine mammary gland cancer

Neoplasia occurs mostly in mammary glands in female dogs and mammary gland cancer is one of the causes of death in these animals cytokeratins are one of the most important of tumor markers for identification of tumor prognosis. In this study, 120 canine malignant tumor samples of mammary glands were studied. From each sample, a section was taken for hematoxylin-eosin staining and two sections for immunohistochemical staining of markers CK5/6 and CK7. Histopathology slides was evaluated by light microscope. The results show that the presence of markers CK7 and CK5/6 had no significant relationship with tumor grade and type (p<0.05). However, it seems that unlike humans, CK5/6 and CK7 is not an independent prognostic factor in canine mammary gland tumors

Modeling of Microstructural Evolution during Homogenization and Simulation of Transient State Recrystallization leading to Peripheral Coarse Grain Structure in Extruded Al-4.5Zn-1Mg Alloy

Materials Science & EngineeringMechanical, Maritime and Materials Engineerin