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Article
Publication date: 5 September 2016

Somaye Akbari, Mehdi Akbari, Mohammad Haghighat Kish and Firoz Mehr Mazaheri

The production of long-lasting fragrant semi-worsted fabrics using dendritic compounds as one of the nano size materials is concerned. Also quantitative assessments of the odour…

211

Abstract

Purpose

The production of long-lasting fragrant semi-worsted fabrics using dendritic compounds as one of the nano size materials is concerned. Also quantitative assessments of the odour intensity of the fragrant fabrics using an electronic-nose (E-nose) are made. The paper aims to discuss these issues.

Design/methodology/approach

The semi-worsted fabrics were perfumed using the second generation of polypropylene-imine (PPI) dendrimer as a host molecules. The ginseng and rosewater fragrances as guest molecules were applied into the PPI dendrimer to produce long-lasting fragrant fabrics. The odour intensity as well as long-lasting properties of the fragrant fabrics perfumed recently and the other sample perfumed one year ago were evaluated via E-nose fabricated in our laboratory. Physical properties of the fragrant fabrics were compared to the non-fragrant ones.

Findings

The interaction between ginseng and rosewater fragrances with the second generation of PPI dendrimer into the semi-worsted fabrics made a long-lasting fragrant fabrics without considerable impacts on bending length, air permeability and wrinkle recovery angles based on statistical analysis. However, the effects of making fragrant fabrics on the increasing weight are significant. In addition, the E-nose was successfully used to monitor the release of ginseng and rosewater fragrance from the fabrics by the response patterns of a temperature-modulated chemo-resistive gas sensor. E-nose analysis showed that the aroma intensity released from the old fragrant semi-worsted fabrics has no obvious diversity from that of new fragrant fabrics.

Originality/value

The findings suggest that the semi-worsted fabrics perfumed with dendritic materials revealed excellent sustained release property.

Details

International Journal of Clothing Science and Technology, vol. 28 no. 5
Type: Research Article
ISSN: 0955-6222

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Article
Publication date: 1 May 1992

C.K. HSIEH, MEHDI AKBARI and HONGJUN LI

A method has been developed for the solution of inverse heat diffusion problems to find the initial condition, boundary condition, and the source and sink function in the heat…

63

Abstract

A method has been developed for the solution of inverse heat diffusion problems to find the initial condition, boundary condition, and the source and sink function in the heat diffusion equation. The method has been used in the development of a source‐and‐sink method to find the boundary conditions in inverse Stefan problems. Green's functions have been used in the solution, and the problems are solved by using two approaches: a series solution approach, and a time incremental approach. Both can be used to find the boundary conditions without reliance on the flux information to be supplied at both sides of the interface. The methods are efficient in that they require less equations to be solved for the conditions. The numerical results have shown to be accurate, convergent, and stable. Most of all, the results do not degrade with time as in other time marching schemes reported in the literature. Algorithms can also be easily developed for the solution of the conditions.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 2 no. 5
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 5 May 2021

Shahin Akbari, Nima Hasanvand, Sadegh Sadeghi, Mehdi Bidabadi and Qingang Xiong

The widespread usage of magnetic nanoparticles (MNPs) requires their efficient synthesis during combustion process. This study aims to present a mathematical model for the…

182

Abstract

Purpose

The widespread usage of magnetic nanoparticles (MNPs) requires their efficient synthesis during combustion process. This study aims to present a mathematical model for the oxidation of MNPs in a counter-flow non-premixed combustion system to produce MNPs, where the key sub-processes during the oxidation reaction are involved.

Design/methodology/approach

To accurately describe structure of flame and determine distributions of temperature and mass fractions of both reactants and products, equations of energy and mass conservations were solved based on the prevailing assumptions that three regions, i.e. preheating, reaction and oxidizer zones exist.

Findings

The numerical simulation was first validated against experimental data and characteristics of the combustion process are discussed. Eventually, the influences of crucial parameters such as reactant Lewis numbers, strain rate ratio, particle size, inert gas and thermophoretic force on structure of flame and combustion behavior were examined. The results show that maximum flame temperature can achieve 2,205 K. Replacing nitrogen with argon and helium as carrier gases can increase flame temperature by about 27% and 34%, respectively. Additionally, maximum absolute thermophoretic force was found at approximately 9.6 × 10–8 N.

Originality/value

To the best of authors’ knowledge, this is the first time to numerically model the preparation of MNPs in a counter-flow non-premixed combustion configuration, which can guide large-scale experimental work in a more effective way.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 8
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 13 January 2020

Mahdi Salehi, Ali Daemi and Farzana Akbari

This study aims to examine the effect of managerial ability on product market competition and corporate investment decisions, specifically, on risk-taking and investment…

939

Abstract

Purpose

This study aims to examine the effect of managerial ability on product market competition and corporate investment decisions, specifically, on risk-taking and investment efficiency.

Design/methodology/approach

The primary measure of managerial ability is Demerjian et al. model. In this study, Herfindahl–Hirschman Index is used to measure product market competition. Regression analysis is used to examine the association between corporate risk-taking and over-investment of free cash flow and product market competition and managerial ability.

Findings

Using firm-year observations from 2011 to 2015, the paper findings suggest that competition discourages managers to invest in risky investment. The study also found that managerial ability has no effect on the association between product market competition and investment decision.

Originality/value

The current study almost is the first study which is conducted on this subject; the results may give strength to further studies.

Details

Journal of Islamic Accounting and Business Research, vol. 11 no. 1
Type: Research Article
ISSN: 1759-0817

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Article
Publication date: 29 November 2018

Farzana Akbari, Mahdi Salehi and Mohammad Ali Bagherpour Vlashani

The purpose of this paper is to investigate the effect of managerial ability on tax avoidance in Tehran Stock Exchange (TSE) and OTC by classifying the income smoother and…

876

Abstract

Purpose

The purpose of this paper is to investigate the effect of managerial ability on tax avoidance in Tehran Stock Exchange (TSE) and OTC by classifying the income smoother and non-income smoother companies based on the theoretical approaches.

Design/methodology/approach

To measure the managerial ability the data envelopment analysis is applied based on the accounting data, company and industry characteristics. In this research, hypotheses are tested for the first time by three statistical methods, namely classical regression models, mixed effect multilevel models, and Bayesian multilevel models, which have never been addressed in Persian accounting research studies. The hypotheses are estimated during a 12-year period from 2004 to 2015 in TSE and OTC. In this research, according to Lucas’s critique, structural change test is used in order to control macroeconomic and political variables affecting the results of the study.

Findings

The results of hypothesis testing by employing three statistical methods suggest that only one hypothesis of this investigation is significant, which shows the significant association of type of market’s impact (exchange of OTC) on the relationship between managerial ability and tax avoidance.

Originality/value

Each company’s performance is affected by various factors. The study intends to mention that the performance of listed companies in the stock market depends heavily on its financial reports. And investors with perceived perception by the reports, can indirectly squeeze their stock indexes with their sudden sale of stocks, and question the company’s performance with losses to the company.

Details

International Journal of Emerging Markets, vol. 13 no. 6
Type: Research Article
ISSN: 1746-8809

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Article
Publication date: 19 December 2018

Farzana Akbari, Mahdi Salehi and Mohammad Ali Bagherpour Vlashani

The purpose of this paper is to investigate the relationship between tax avoidance, firm value and managerial ability in Tehran Stock Exchange and Over the Counter (OTC)…

2033

Abstract

Purpose

The purpose of this paper is to investigate the relationship between tax avoidance, firm value and managerial ability in Tehran Stock Exchange and Over the Counter (OTC), according to the related theoretical foundations.

Design/methodology/approach

To calculate the managerial ability in this study, DEA is used based on the accounting data, company profile and industry and the hypotheses are estimated in a period of 12 years during 2004 to 2015 in TSE and OTC. Within the previous studies, to test the hypotheses, only the classical regression method is usually used and most of the times the effect of macroeconomic variables is not considered. In this study, in a new act for testing the hypotheses, three statistical methods are used, that is, classical regression models, mixed effects multilevel models and Bayesian multilevel models. Also in this study, the test of structural change is used to control the effects of macroeconomic variables, like inflation and other economic and political influence, on the results.

Findings

The results of these three methods show that the effect of income smoothing and earnings quality on the relationship between tax avoidance and firm value are significant.

Originality/value

Although several studies are conducted so far on the subject of the study, the current study is the first project which combined Bayesian econometrics. Therefore, the results are quite noble.

Details

International Journal of Organizational Analysis, vol. 27 no. 1
Type: Research Article
ISSN: 1934-8835

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Article
Publication date: 25 April 2020

Mahdi Salehi, Ali Daemi Gah, Farzana Akbari and Nader Naghshbandi

The purpose of this study is to analyze the predictability of firm level data for determining macroeconomic indicators such as unemployment.

238

Abstract

Purpose

The purpose of this study is to analyze the predictability of firm level data for determining macroeconomic indicators such as unemployment.

Design/methodology/approach

This study uses quarterly GDP and unemployment data manually collected from the Statistical Center of Iran (SCI). Accounting numbers are also collected from the Tehran Stock Exchange library for the 2004-2015 period. Dispersion of earnings growth provides related data about labour reallocation, unemployment change and finally aggregate output. To summarize, this study attempts to examine the effect of these variables using classical and Bayesian approaches.

Findings

At a firm level, our results suggest that sectoral shift in previous years is likely to increase labour reallocation in subsequent years. At the macro level, the results reveal that dispersion of earnings growth and labour reallocation has a negative and positive impact on unemployment changes, respectively. However, the study suggests no significant relationship between stock return and unemployment changes. Consequently, we determine that the real estimates of macroeconomic indicators have predictive power because nominal estimates are not statistically associated with firm-level details. Finally, the results obtained from classical and Bayesian approaches suggest similar findings, thus confirming the robustness of our conclusions. Note that, based on Bayesian approach, the nominal reallocation has predictive power in unemployment rate.

Originality/value

The study is the first conducted in a developing country and the results provide important insight into current line of accounting literature.

Details

International Journal of Organizational Analysis, vol. 29 no. 1
Type: Research Article
ISSN: 1934-8835

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Article
Publication date: 4 December 2018

Marjan Goodarzi, Saeed Javid, Ali Sajadifar, Mehdi Nojoomizadeh, Seyed Hossein Motaharipour, Quang-Vu Bach and Arash Karimipour

With respect to two new subjects, i.e. nanofluids and microchannels, in heat transfer systems and modern techniques used for building them, this paper aims to study on effect of…

227

Abstract

Purpose

With respect to two new subjects, i.e. nanofluids and microchannels, in heat transfer systems and modern techniques used for building them, this paper aims to study on effect of using aluminum oxide nanoparticles in non-Newtonian fluid of aqueous solution of carboxy-methyl cellulose in microtube and through application of different slip coefficients to achieve various qualities on surface of microtube.

Design/methodology/approach

Simultaneously, the effect of presence of nanoparticles and phenomenon of slip and temperature jump has been explored in non-Newtonian nanofluid in this essay. The assumption of homogeneity of nanofluid and fixed temperature of wall in microtube has been used in modeling processes.

Findings

The results have been presented as diagrams of velocity, temperature and Nusselt Number and the investigations have indicated that addition of nanoparticles to the base fluid and increase in microtube slip coefficient might improve rate of heat transfer in microtube.

Originality/value

The flow of non-Newtonian nanofluid of aqueous solution of carboxy methyl cellulose-aluminum oxide has been determined in a microtube for the first time.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 5
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 28 November 2018

M.A. Mushahhid Majeed and Sreehari Rao Patri

This paper aims to resolve the sizing issues of analog circuit design by using proposed metaheuristic optimization algorithm.

243

Abstract

Purpose

This paper aims to resolve the sizing issues of analog circuit design by using proposed metaheuristic optimization algorithm.

Design/methodology/approach

The hybridization of whale optimization algorithm and modified gray wolf optimization (WOA-mGWO) algorithm is proposed, and the same is applied for the automated design of analog circuits.

Findings

The proposed hybrid WOA-mGWO algorithm demonstrates better performance in terms of convergence rates and average fitness of the function after testing it with 23 classical benchmark functions. Moreover, a rigorous performance evaluation is done with 20 independent runs using Wilcoxon rank-sum test.

Practical implications

For evaluating the performance of the proposed algorithm, a conventional two-stage operational amplifier is considered. The aspect ratios calculated by simulating the algorithm in MATLAB are later used to design the operational amplifier in Cadence environment using 180nm CMOS standard process.

Originality/value

The hybrid WOA-mGWO algorithm is tailored to improve the exploration ability of the algorithm by combining the abilities of two metaheristic algorithms, i.e. whale optimization algorithm and modified gray wolf optimization algorithm. To build further credence and to prove its profound existence in the latest state of the art, a statistical study is also conducted over 20 independent runs, for the robustness of the proposed algorithm, resulting in best, mean and worst solutions for analog IC sizing problem. A comparison of the best solution with other significant sizing tools proving the efficiency of hybrid WOA-mGWO algorithm is also provided. Montecarlo simulation and corner analysis are also performed to validate the endurance of the design.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 38 no. 1
Type: Research Article
ISSN: 0332-1649

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Abstract

Details

Business Strategies and Ethical Challenges in the Digital Ecosystem
Type: Book
ISBN: 978-1-80455-069-4

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