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Using turbulators, obstacles, ribs, corrugations, baffles and different tube geometry, and also various arrangements of these components have a noticeable effect on the shell and tube heat exchangers (STHEs) thermal-hydraulic performance. This study aims to investigate non-Newtonian fluid flow characteristics and heat transfer features of water and carboxyl methyl cellulose (H₂O 99.5%:0.5% CMC)-based Al₂O₃ nanofluid inside the STHE equipped with corrugated tubes and baffles using two-phase mixture model.

Five different corrugated tubes and two baffle shapes are studied numerically using finite volume method based on SIMPLEC algorithm using ANSYS-Fluent software.

Based on the obtained results, it is shown that for low-mass flow rates, the disk baffle (DB) has more heat transfer coefficient than that of segmental baffle (SB) configuration, while for mass flow rate more than 1 kg/s, using the SB leads to more heat transfer coefficient than that of DB configuration. Using the DB leads to higher thermal-hydraulic performance evaluation criteria (THPEC) than that of SB configuration in heat exchanger. The THPEC values are between 1.32 and 1.45.

Using inner, outer or inner/outer corrugations (outer circular rib and inner circular rib [OCR+ICR]) tubes for all mass flow rates can increase the THPEC significantly. Based on the present study, STHE with DB and OCR+ICR tubes configuration filled with water/CMC/Al₂O₃ with f = 1.5% and d_np = 100 nm is the optimum configuration. The value of THPEC in referred case was 1.73, while for outer corrugations and inner smooth, this value is between 1.34 and 1.57, and for outer smooth and inner corrugations, this value is between 1.33 and 1.52.

It has been suggested that there is a link between the dietary intake of certain nutrients and the risk of prostate cancer. The aim of this study is to examine the associations between dietary intakes of all nutrients and the risk of prostate cancer in Kermanshah.

This case-control study was conducted in Kermanshah, a province in the west of Iran in November of 2016. The sample consisted of 50 patients with confirmed prostate cancer, and 150 healthy men who matched in age with these cases and did not have any symptoms of prostate disorder were chosen as controls. Dietary intakes were collected by a semi-quantitative food frequency questionnaire that contained 147 food items and were then analyzed by Nutritionist 4 software.

After adjustment for potential confounding factor, highest tertile compared to lowest tertile of dietary vitamin E intake [odds ratio (OR) = 0.21; 95% confidence interval (CI) = 0.05-0.89], lycopene intake (OR = 0.11; 95% CI = 0.01-0.86) and magnesium intake (OR = 0.02; 95% CI = 0.01-0.55) had a protective effect on the incidence of prostate cancer. However, there were no associations between dietary intakes of fiber, vitamin A, vitamin D, vitamin B₁₂, folate and calcium with prostate cancer.

The finding suggests that the dietary intakes of vitamin E, lycopene and magnesium could decrease the risk of prostate cancer. Nevertheless, dietary intake of other nutrients such as fiber, calcium, vitamins D, A, B₁₂ and folate was not associated with prostate cancer.

This study aims to investigate the contingent roles real effective exchange rates (REERs) play in mediating the effects of oil revenue on the agriculture sector value-added in 25 major and minor oil-exporting (MIOEC) countries during the period of 1975–2014.

The panel autoregressive distributed lag (ARDL) estimator proposed by Pesaran et al. (1999) was relied upon to achieve the objectives of the study. This estimator involves a pool of small cross-sectional units over a long-time span that covers for 25 oil-exporting countries over 39 years (1975–2014).

This paper reveals the following findings. Firstly, oil revenue has a direct negative effect on agricultural value-added in the short- and long-term. This finding holds for full sample and subsamples of major oil-exporting (MAOEC) and MIOEC countries. Further assessment reveals that the magnitude of the impact is larger for MAOEC than that of the MIOEC. Secondly, the finding for the long-run effect shows that the contingent effect of real exchange rate on the nexus between oil revenue and agricultural value-added is negative and statistically significant at the conventional level for the full sample. This suggests that, in the long-run, the appreciation in real exchange rates exacerbate the negative marginal effects of oil revenue on agricultural value-added in all oil-exporting countries. However, when sub-samples of MAOEC and MIOEC are considered, the contingent effect disappeared (become insignificant) in MAOEC while it is positive and statistically significant in MIOEC. Thus, in the long-run, the appreciation in real exchange rates diminishes the negative marginal effects of oil revenue on agricultural value-added in MIOEC. While oil revenue has a direct negative effect, its effect is also moderated by the variations in REERs in MIOEC in the long-run. Finally, in the short-run, fluctuations in the real exchange rate do not matter for the nexus of oil revenue and agriculture sector in these countries whether minor or MAOEC countries.

This study contributes to the debate in the empirical literature on the Dutch disease effect and “oil curse”. Using the appropriate panel ARDL empirical framework, it provides evidence on how exchange rate variations in the oil-exporting countries influence the nature of the effects of the oil revenue on agricultural sectors in the long-run but not in the short-run. Contingent effects of REERs only appear to exist in MIOEC in the long-run.

This study aims to examine the reuse of plastic and fly ash (FA) to improve the soil and achieve sustainable development goals.

Sand from the Anzali port was reinforced with Geopet (GP) and stabilized with FA plus 3% sodium hydroxide. The GP was placed in FA-stabilized soil and the California bearing ratio (CBR), and unconfined compressive strength (UCS) tests were performed on samples at the optimum moisture content.

The results showed that the improvement in the optimum CBR was 174.9%. The UCS increased 15.25% and 48.65% in soil reinforced with three layers of GP plus 15% FA over those containing 10% and 5% FA, respectively. Additionally, the current analysis used response surface methodology (RSM) to investigate the impact of FA percentage, GP layers and their interaction on CBR. The results highlight the efficacy of the used RSM model, as evidenced by the significantly low p-value (<0.0001).

This demonstrates the suitability and effectiveness of RSM for evaluating CBR in this scientific study.

Image annotation plays an important role in image retrieval process, especially when it comes to content-based image retrieval. In order to compensate the intrinsic weakness of machines in performing cognitive task of (human-like) image annotation, leveraging humans’ knowledge and abilities in the form of crowdsourcing-based annotation have gained momentum. Among various approaches for this purpose, an innovative one is integrating the annotation process into the CAPTCHA workflow. In this paper, the current state of the research works in the field and experimental efficiency analysis of this approach are investigated.

At first, and with the aim of presenting a current state report of research studies in the field, a comprehensive literature review is provided. Then, several experiments and statistical analyses are conducted to investigate how CAPTCHA-based image annotation is reliable, accurate and efficient.

In addition to study of current trends and best practices for CAPTCHA-based image annotation, the experimental results demonstrated that despite some intrinsic limitations on leveraging the CAPTCHA as a crowdsourcing platform, when the challenge, i.e. annotation task, is selected and designed appropriately, the efficiency of CAPTCHA-based image annotation can outperform traditional approaches. Nonetheless, there are several design considerations that should be taken into account when the CAPTCHA is used as an image annotation platform.

To the best of the authors’ knowledge, this is the first study to analyze different aspects of the titular topic through exploration of the literature and experimental investigation. Therefore, it is anticipated that the outcomes of this study can draw a roadmap for not only CAPTCHA-based image annotation but also CAPTCHA-mediated crowdsourcing and even image annotation.

The purpose of this paper is to investigate the effects of combined risperidone (RIS) and pivotal response treatment (PRT) in children with autism spectrum disorder (ASD).

In all, 34 children diagnosed with ASD (mean age of 12.36 years) were randomly divided into two groups: an RIS treatment group (n=18) and an RIS plus PRT (n=16). Communication skills were evaluated with the child communication checklist (CCC).

Total score of the CCC was increased in both groups after three months compared with the score prior to treatment. The total score of the CCC was significantly higher in the combined treatment group than in the RIS group.

Treatment with RIS combined with PRT may result in a better outcome in communication skill for children with autism than RIS training alone.

According to very small dimensions of the microchannels, producing a microchannel with smooth surfaces is approximately impossible. The surface roughness can have a specific effect on microchannel performances. This paper aims to investigate the changes in friction and pressure drop in the microchannels by considering the different roughness elements on microchannel wall and changes in elementary geometry and flow conditions. Results show a significant effect of roughness on the pressure drop and friction.

Two-dimensional fluid flow in the rough microchannels is analyzed using FLUENT. Microchannels have a height of 50 µm. Water at room temperature (25°C) has been used as working fluid. The Reynolds numbers are considered in laminar flow range and from 50 to 300.

The results show that the value of friction factor reduces nonlinearly with an increase in Reynolds number. But, the pressure drops and the Poiseuille number in the microchannels increase with an increase in Reynolds number. The values of the pressure drop and the friction factor increase by increasing the height and size of the roughness elements, but these values reduce with an increase in the distance of roughness elements.

The roughness elements types in this research are rectangular, trapezoidal, elliptical, triangular and complex (composed of multiple types of roughness elements). The effects of the Reynolds number, roughness height, roughness distance and roughness size on the pressure drop and friction in the rough microchannels are investigated and discussed. Furthermore, differences between the effects of five types of roughness elements are identified.

The purpose of this paper is to investigate factors affecting the students’ learning of the concepts of the accounting information systems (AIS) in Iran.

The statistical population of the study is the accounting and auditing students (Master’s degree) who have the lesson of AIS at state and private universities, as well as the institutes of higher education in 2017. The Likert scale has been used to design questionnaires. Further, the data were analyzed using structural equation modeling with the partial least squares technique.

Overall, after analyzing and comparing the results of the hypotheses, it was found that, respectively, “assistance to students,” “the power of critical thinking,” “academic professors skills,” “kind of transition to university,” “AIS course structure,” “proper timing of AIS presentation,“ “presentation of a prerequisite course” and finally, “appreciation of AIS” have the greatest impact on the level of student learning in AIS lesson. The results of this paper showed that “teaching style” and “having the previous background of the information system concepts” do not have a statistically significant effect on students’ general learning.

Without any overstatement, this paper will warn educational authorities in emerging countries that lack of attention to factors affecting university students’ learning can have serious consequences for the market of a country. Other than that, this paper will make university professors aware of the effects of effective methods for better student learning in the field of information technology, so that they can make a better assessment of the importance of AIS course.

Independent auditors play an important role in increasing the reliability of financial information by giving their professional opinion on the financial statements of business units. Therefore, the purpose of this study is to investigate the relationship between the audit adjustments and financing of companies.

The sample of the study includes 173 Iranian companies listed on the Tehran Stock Exchange (TSE) between 2010 and 2017.

There is no significant association between the profit incremental audit adjustments (Disagreement) and financing of companies in the current year and the following year through a loan. Furthermore, there is no meaningful relationship between the earnings downward/upward audit adjustments (Disagreement) and the financing of companies in the current year and the following year through ordinary stocks. However, there is a meaningful relationship between the profit downward audit adjustments (Disagreement) and the financing of firms in the current year through a loan. In general, as Iran's economy is facing severe economic sanctions, the existence of a high inflation rate has led to a steady increase in the stock prices of Iranian companies; hence, investors regardless of audit reports prefer to invest their money in the stock market so that it does not lose its purchasing power. Under these disaster economic circumstances, creditors are less willing to lend to companies with lower profits.

The results of the current study extend the knowledge of previous studies as financial pressures from economic sanctions have both positive and negative psychological effects on corporate financing.

A direct power control (DPC) of the doubly-fed induction generator (DFIG) is presented. A new method, which is based on the rotation of the space sector, clockwise or vice versa, is proposed to improve the performance of the switching table. Then, it is combined with a fuzzy system to have advantages of both rotation sector and fuzzy controller. The paper aims to discuss these issues.

In this paper, a new DPC of the DFIG is presented. To improve the performance of the switching table, a new method is proposed. The method is based on the rotation of the space sector, clockwise or vice versa. The excellence of the proposed method is proven. Then, it is shown that the performance of the system can be enhanced by using a fuzzy logic controller. The rotation method is combined with a fuzzy system.

Simulation shows that although sector rotation and fuzzy controller can improve the performance of the DFIG, a combination of both demonstrates a smoother response in order that reactive and active power ripples and THD of the injected current decrease in different speeds. Also, it is demonstrated that the proposed method is robust against parameters variations. However, a hardware experiment should be performed to be practically verified.

A sector rotation is proposed and its effect on the performance of the DFIG is considered. A simple method to write rules table is presented and the performance of sector rotation and fuzzy controller on the DFIG is analysed.