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This paper explores the challenges of conducting qualitative research from ELT (English Language Teaching) Ph.D. candidates' perspectives.

The participants of the study consisted of 30 Iranian Ph.D. students majoring in ELT. The semi-structured interview was employed to investigate the heart of experiences, issues and concerns of participants with regard to conducting qualitative research (QLR) challenges. To analyze the collected data, the recorded interviews were transcribed, and then the grounded theory approach was employed (Charmaz, 2006).

The results revealed that the major challenges of the participants consist of the credibility of QLR in ELT contexts, hermeneutic and fuzzy nature of QLR, qualitative data analysis and interpretation, publishing qualitative findings and the system of measuring professors' productivity.

The findings may help professors, mainly EFL ones, in research mentoring and developing research syllabi for graduate students. In addition, it may motivate Ph.D. candidates to employ QLR methods in their research studies. The pedagogical and theoretical implications of the study are discussed at the end of the paper.

Throughout human history, the occurrence of disasters has been inevitable, leading to significant human, financial and emotional consequences. Therefore, it is crucial to establish a well-designed plan to efficiently manage such situations when disaster strikes. The purpose of this study is to develop a comprehensive program that encompasses multiple aspects of postdisaster relief.

A multiobjective model has been developed for postdisaster relief, with the aim of minimizing social dissatisfaction, economic costs and environmental damage. The model has been solved using exact methods for different scenarios. The objective is to achieve the most optimal outcomes in the context of postdisaster relief operations.

A real case study of an earthquake in Haiti has been conducted. The acquired results and subsequent management analysis have effectively assessed the logic of the model. As a result, the model’s performance has been validated and deemed reliable based on the findings and insights obtained.

Ultimately, the model provides the optimal quantities of each product to be shipped and determines the appropriate mode of transportation. Additionally, the application of the epsilon constraint method results in a set of Pareto optimal solutions. Through a comprehensive examination of the presented solutions, valuable insights and analyses can be obtained, contributing to a better understanding of the model’s effectiveness.

The purpose of this paper is to develop the C-shaped quality function deployment (QFD) 3D Matrix for service applications.

The C-shaped QFD 3D Matrix proposed by Vezzetti et al. (2016) has been developed for simultaneous analysis of the relationships among three sets of factors of customer requirements, service design characteristics and service performance indicators. The three sets of factors have been determined and based on their interrelationships, 3D and concurrent houses of quality have been formed. Then, service design characteristics and service performance indicators have been prioritized. The obtained priorities have been also compared with traditional concurrent model of QFD.

The findings obtained from the traditional and developed approach seem different, implying that applying the C-shaped QFD 3D Matrix provides a more real perspective of concurrent engineering and the results in different set of priorities of service factors.

The case study was limited to banking services. If the developed approach is used in other institutes, the prioritization of service design characteristics and service performance indicators might be changed.

Compared to Vezzetti et al. (2016) who proposed the C-shaped QFD 3D Matrix for analyzing interrelationships among two customers and a provider, or two providers and a customer, in this paper, the C-shaped QFD 3D Matrix has been developed for analyzing interrelationships among three sets of factors of customer requirements, service design characteristics and service performance indicators.

This paper aims to study the fluid flow and heat transfer through a spiral double-pipe heat exchanger. Nowadays using spiral double-pipe heat exchangers has become popular in different industrial segments due to its complex and spiral structure, which causes an enhancement in heat transfer.

In these heat exchangers, by converting the fluid motion to the secondary motion, the heat transfer coefficient is greater than that of the straight double-pipe heat exchangers and cause increased heat transfer between fluids.

The present study, by using the Fluent software and nanofluid heat transfer simulation in a spiral double-tube heat exchanger, investigates the effects of operating parameters including fluid inlet velocity, volume fraction of nanoparticles, type of nanoparticles and fluid inlet temperature on heat transfer efficiency.

After presenting the results derived from the fluid numerical simulation and finding the optimal performance conditions using a genetic algorithm, it was found that water–Al₂O₃ and water–SiO₂ nanofluids are the best choices for the Reynolds numbers ranging from 10,551 to 17,220 and 17,220 to 31,910, respectively.

The purpose of this paper is to examine the dynamical behavior of a combined three-story building with a 3D panel wall system including a soft story irregularity at the very first floor by doing a shaking table test. The upper two stories of the model were made out of the 3D panel system, while the first story was constructed only with moment-resisting RC frames.

Besides the experimental program, the numerical finite element method was implemented for the verification of the experimental results. In the experimental study, the building responses including the floors’ accelerations and drifts were considered, and the seismically vulnerable zones were reported and compared with that provided by the implemented FEM-based program.

After the shaking table test, the major cracks appeared at the end of each column and beam-column connections. Some negligible cracks were also visible around the beam-panel connections. However, no crack was seen in the upper stories. The lateral deformation of the studied building was investigated under the applied ELC25 and NGH135 earthquakes. Under the both aforementioned ground motion records, the first story drift was larger than two upper stories, since the moment-resisting frame was a soft story. The hysteretic relation between the shear and displacement for each story was studied. Under the applied ELC25 earthquake, the system remains linear and the stiffness of each story is obtainable as well.

This is the first time when the dynamical behavior of a combined system is studied and tested experimentally and numerically for data validation. Regarding the response of the assumed combined structure, the 3D panel system has a remarkable rigidity with respect to the conventional RC frames, also 3D panels have less weight than the moment-resisting frames.

This paper aims to numerically investigate the nanofluid flow, heat transfer and entropy generation during natural convection in an annulus.

The lattice Boltzmann method is used to simulate the velocity and temperature fields. Furthermore, some special modifications are applied to make the lattice Boltzmann method capable for simulation in the curved boundary conditions. The annulus is filled with CuO-water nanofluid. The dynamic viscosity of nanofluid is estimated using KLL (Koo-Kleinstreuer-Li) model, and the nanoparticle shape effect is taken account in calculating the thermal conductivity. On the other hand, the local/volumetric entropy generation is used to show the irreversibility under influence of different parameters.

The effect of considered governing parameters including Rayleigh number (103<Ra < 106); nanoparticle concentration (0<<0.04) and configuration of annulus on the flow structure; temperature field; and local and total entropy generation and heat transfer rate are presented.

The originality of this work is using of lattice Boltzmann method is simulation of natural convection in a curved configuration and using of Koo–Kleinstreuer–Li correlation for simulation of nanofluid.