Search

Pipeline systems are widely used in gas refineries, oil factories chemical power plants. It is important to measure the fluid temperature in this pipeline. Numerous cases, however, exist where the internal fluid temperature is not available and only an outside wall temperature measurement is feasible. Recently inverse heat transfer problems have been analyzed for the situations where a direct measurement of boundary/initial conditions, or thermophisical properties are difficult, or indeed impossible, to carry out. Various numerical approaches have been proposed to estimate fluid temperature in the pipes. In this study, the analytical method is applied to solve the one-dimensional inverse heat conduction problem, in order to estimate fluid temperature in the pipes, based on the exact outer wall temperature. The fluid temperature is assumed to be a polynomial. The unknown polynomial coefficients are found by combining the method of Duhamel's theorem and the least squares method. The results show that the fluid temperature in the pipes can be accurately estimated by using the inverse heat transfer method.

Background & Aim: The goal of asthma treatment and management is its control. Yoga is one of the complementary treatments which is used to control asthma. This study aimed to determine the effect of yoga breathing exercises on asthma control in 5-11 year-old children with asthma. Methods & Materials: In this quasi-experimental study, 84 children with asthma, aged 5-11 years, referred to Asthma and Allergy Clinic of Aliasghar hospital, were included in the study in 2018. The participants were selected through continuous sampling and non-randomly allocated to an experiment- or a control group (42 in each group). The Childhood Asthma Control Test (C_ACT) was used to collect the data, before and after the intervention. The intervention included yoga breathing exercises. The researcher trained the children and their parents at the clinic and these exercises were performed by the children for two months, with parental supervision at home. Data were analyzed by the SPSS software version 21 using independent t-test, paired t-test, chi-square and Fishers exact test. Results: The mean of age was 8.42(1.96) for the experiment group and 8.11(1.8) for the control group. In the experiment group, 76.2% were male, and 23.8% were female. In the control group, 73.8% were male and 26.2% were female. Before the intervention, the mean of asthma control score was 17.81±4.42 for the experiment group and 18.38±4.24 for the control group but this difference was not statistically significant (P=0.54). After the intervention, the mean of asthma control score for the experiment group and control group was 21.69±1.6 and 19.83±2.4, respectively. This difference was statistically significant (P˂0.001). Conclusion: Yoga breathing exercises improved asthma in children. According to the results, yoga breathing exercises are suggested as scientific, simple and refreshing techniques in children with asthma. Clinical trial registry: IRCT20180501039489N1

The aim of this research is to recognize earnings management of the firms listed in Tehran Stock Exchange using changes in asset turnover (ATO) and profit margin (PM). ATO/PM model and Jones adjusted abnormal accruals model have been used to recognize upward and downward earnings management. Statistical population contains 133 firms during 2004-2011. The correlations tests, the mean equality tests such as t-student & Welch, and also panel/pooled regression models have been used to test the research hypotheses. Findings indicate that contemporaneous increases in PM and decreases in ATO cannot be as a recognizer of upward earnings management, and also contemporaneous decreases in PM and increases in ATO cannot be as a recognizer of downward earnings management. Also, results show that Jones adjusted abnormal accruals model as compared to ATO/PM model has incremental and greater relative information content in recognition of earnings management.

The aim of this research is to investigate the explanatory power of asset turnover (ATO)/Profit Margin (PM) model in determining of changes of operating income of listed companies in Tehran Stock Exchange. Dependent variable is ratio of changes of operating income to net operating assets in forward year that is used to measure the information content of ATO/PM model in identifying earnings management. In this study, we propose a simple diagnostic of earnings management that relies on the widely held notion underlying DuPont analysis that sales is a fundamental driver of a firm’s investment and income, and that net operating assets on the balance sheet and net operating income on the income statement should vary directly with sales. Moreover, we note that changes in ATO and PM in opposite directions could signal earnings management. Independent variables contain upward and downward EM based on ATO/PM model. Also, operating income to net operating assets ratio in current year, changes of operating income to net operating assets ratio in current year, to net operating assets to sale ratio in current year, changes of net operating assets to sale ratio in current year, changes of ATO, changes of PM, components of managed accrual items based on abnormal accrual items (Jones adjusted Model), and market value to book value were applied as control variables. Statistical population contains 133 companies during 2004-2011. The panel/pooled regression models exerted to testify research hypotheses. Findings indicate that ATO/PM model compared with Jones adjusted abnormal accruals items model is of less relative information content in identifying earnings management.