In this work, the transient process of surge in a gas turbine engine has been investigated numerically. A one-dimensional stage-by-stage mathematical model has been developed, which can describe the system behavior during aerodynamic instabilities. It is demonstrated that, these instabilities can be stabilized by the use of active control strategies, such as air bleeding and air injection. Both steady and unsteady active control systems were considered. In the steady case, mass is removed at a fixed rate from the diffuser, or mass is injected at a fixed rate into the first stage of the compressor. In the unsteady control, the rate of bleeding or injection is linked with the amplitude and the frequency of the upstream pressure disturbances. Results show that both steady and unsteady strategies eliminate surge disturbances and suppress the instabilities. Therefore, they extend the stable operating range of compressor. It is shown that smaller amount of compressed air needs to be removed in the unsteady control case. Also, a variable area diffuser is shown to be able of suppressing surge instabilities. Active control of instabilities, caused by sinusoidal perturbations of the inlet total pressure, was also investigated, which showed to destabilize the stable operating condition at the design point.

The aim of this study is to understand the concept of information Avoidance in terms of origin, effective factors, behaviors, areas of the previous studies, and research gaps. This research was conducted by systematic review method using Kitchenham and Charters (2007) framework. By reviewing internal and external databases and studying the abstracts of retrieved articles with related keywords, 65 related articles were identified and after refinement, 49 related articles were reviewed without time limitation. After studying the articles related to information Avoidance, and using the content analysis approach, the contents were categorized into several thematic categories and the questions were answered according to the aims of the research. The findings suggest that the origins of information Avoidance could be traced back to theories such as cognitive dissonance theory of Festinger (1957), uncertainty reduction theory of Gudykunst (1985), and models such as Johnson’s (1997) and Wilson’s (1999). The most important factors influencing information Avoidance could be classified into two categories of Hedonic and Strategic factors. The factors of hedonic category are preferences for resolution of compound lotteries, risk, loss, and disappointment aversion, anxiety, attention, regret aversion, optimism maintenance, dissonance Avoidance, and belief investments. Strategic factors also fall into two categories: intrapersonal strategic Avoidance (avoiding dynamic inconsistency, resisting temptation, motivation maintenance, avoiding projection biases, abdicating responsibility and saving it for later) and interpersonal strategic Avoidance (avoiding spoiling information about themselves or receiving information about others, which causes a change in their attitudes toward them). Information Avoidance behaviors are then introduced which include physical Avoidance, inattention, biased interpretation of information, forgetting, and self-handicapping. Also, the contexts in which information Avoidance has been discussed so far include health, risk information, social and news media, emotional relationships, and smoking, using common information Avoidance assessment tools such as questionnaires, interviews, modeling, laboratory observation, and task defining are investigated. Finally, two of the important research gaps in this field are the lack of a comprehensive model for information Avoidance that is responsive to any society and any problem, and the need to pay more attention to information Avoidance in the field of knowledge and information science.

Separating management jobs and ownership imposes agency problem among different groups of stakholders. Corporate Governance in organizations is a mechanism for mitigating the problem. Also, in different organizations, tax computation and payment is viewed as an interesting subject. Investors demand for increasing earnings and firm’s value that make them to reduce the amount of taxes and may lead to less payment of taxs. Nevertheless, the public ask for companies’ recognition of fair amount of taxes and companies’ regular payments of taxes. In this environment, corporate governance may create balance between the public’s and companies’ interests.This study investigates the relationships between some indexes of corporate governance, such as institutional ownership, board independency and board size, and the issue of tax Avoidance. For this purpose, we studied 146 companies listed in the Tehran Stock Exchange, during 2001-2012. The results from 1227 firm-year data within an unbalanced panel data model showed no significant relationship between corporate governance and tax Avoidance. Additionally, findings showed a negative significant relationship between control variables of profitability and firm’ size, and a positive significant relationship between tax auditing and tax Avoidance.

The main purpose of this survey is to investigate the factors influencing brand Avoidance intention through customer attitude towards brand Avoidance. Among Rasht citizens 268 individuals who have had an experience of avoiding Chinese brands were selected. A researcher made questionnaire (its validity is tested by two approaches, including face validity and confirmatory factor analysis and its reliability is examined using alpha cronbach (87%)) is distributed among samples. Findings reveal that customer’ s attitude towards brand Avoidance has mediated the relationship between perceived risk of using brand and brand Avoidance intention and it has played a role of mediator variable between anti brand activism and brand Avoidance intention. Consequently, two most important factors that affect customer brand Avoidance would be the anti-brand activism shown by unsatisfied customer and his/ her perceived risk of using the brand.

The present study was an attempt to investigate the impact of some factors on tax Avoidance and present an optimal tax Avoidance prevention model. The study is quantitative in terms of approach and falls within the category of library and documentary studies in terms of data collection method. Since the present library study is conducted using the real data of companies, the required data were collected from various sources such as financial statements, compact discs of the stock exchange market, the software developed by Tadbir pardaz IT group and the Rahavard-e Novin software. The population of the study includes 99 active companies listed on Tehran Stock Exchange. Accordingly, the financial data collected during 2008-2020 from companies listed on the Tehran Stock Exchange was annually studied. The researcher presented his final model after estimating 21 regressions using the Stepwise method. The results suggest that company complexity, corporate governance, accounting variables (quality of disclosure, fraudulent financial reporting, liquidity and intangible assets) and accounting income variables (quality of accruals, earning transparency and dividends) have a significant effect on tax Avoidance.