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In this study, both flame retardancy and sustainability properties were combined in the chenille yarn so that functional and sustainable upholstery fabrics can be produced with optimum energy consumption. The chenille yarn samples were produced from recycled polyester (rPET)-blended binder yarns and fully drawn yarn (FDY) polyester pile yarn. While the pile component of the chenille samples was kept constant, the lock yarns were manufactured as 50% r-PET-50% virgin polyester (PES), 100% r-PET and 100% PES. The binder yarns were also produced in two groups. In the first group, a 2-passage draw frame was used, while a 3-passage draw frame was used in the second group. The chenille yarn samples were applied flame-retardant (FR) finishing.

The knitted upholstery fabric samples were produced from chenille yarn samples via flat knitting machines. The knitted fabrics were applied flame retardancy, bursting strength and abrasion resistance tests according to related standards.

The test results were analysed, and so the effect of r-PET ratio and draw frame passage number on upholstery fabric flame retardancy, bursting strength and abrasion resistance performance properties were revealed. It was concluded that the number of draw frame passages and the recycled fibre content have no important effect on the flame retardancy. On the other hand, it has been observed that the bursting strength decreases as the recycled fibre content increases and bursting distention results are close to each other. It was seen that the draw frame passage number has no significant effect on both bursting strength and distention. It was revealed that both r-PET fibre content and draw frame passage number have significant effect on abrasion resistance. The samples with 2 draw frame passages provide higher abrasion resistance compared to those with 3 draw frame passage. The lowest abrasion resistance was obtained with 100% r-PET fibre content and the highest abrasion resistance was obtained with 50% r-PET-50% PES.

The results will provide enough knowledge for sustainable chenille yarn design. The recycled fibre content and draw frame passage number can be optimised, and so sustainable chenille yarns can be produced with less energy consumption. Future studies will involve producing chenille yarns with different linear densities and varying draw frame combinations, such as 1, 2 and 3 passages.

Heat exchangers (HEXs) are extensively used in many applications such as heating and cooling systems. To increase the thermal performance of HEXs, nano-sized particles could be added to the base working fluid which can improve the thermophysical properties of the fluid. In addition, further improvement in the thermal performance of nanofluids can be obtained by using two or more different nanoparticles which are known as hybrid nanofluids. This paper aims to improve the thermal efficiency of U-type tubular HEX (THEX) by using CuO-Al₂O₃/water hybrid nanofluid.

Numerical simulation has been used to model THEX with various configurations. Also, CuO-Al₂O₃/water hybrid nanofluid has been experimented in THEX in two various modes including parallel (PTHEX) and counter flow (CTHEX) regarding to the numerical findings. Hybrid nanofluids have been prepared in two particle concentrations and compared with CuO/water nanofluid at the same concentrations and also with water.

The numerical simulation results showed that adding fins and also using hybrid nanofluid can increase heat transfer rate in HEX. However, adding fins cannot be a good option in U-type THEX with lower diameter because it increases pressure drop notably. Experimental results of this work illustrated that using Al₂O₃-CuO/water hybrid nanofluid in the THEX improved thermal performance significantly. Maximum enhancement in overall heat transfer coefficient of THEX by using CuO-Al₂O₃/water nanofluid in 0.5% and 1% concentrations achieved as 9.5% and 12%, respectively.

The obtained findings of the study showed the positive effects of using hybrid type nanofluid in comparison with single type nanofluid. In this study, numerical and experimental analysis have been conducted to investigate the effect of using hybrid type nanofluid in U-type HEX. The obtained results exhibited successful utilization of CuO-Al₂O₃/water hybrid type nanofluid in HEX. Moreover, it was observed that thermal performance analysis of the nanofluids without any experiment can be done by using numerical method.

Along with accounting scandals in the past, academics, researchers, and legislators have focused on fraud. The purpose of this study is to examine postgraduate and doctoral studies, articles, and books about forensic accounting and fraud audit published between the years 2008 and 2018 in Turkey. For this purpose, a total of 96 studies have been examined and 35 of these are master’s theses, 10 of them are PhD theses, 45 of them are articles, and six of them are books. These studies were presented in tables as classified. The studies examined in our research are summarized as year they were published, the author, and the scope of the topic and in terms of results. The conclusions of this study can be summarized as follows: (a) the majority of thesis published about forensic accounting and fraud audit are in 2011 and following years. In addition, most of the theses are focused on forensic accounting review rather than fraud audit. (b) Results in the articles reviewed are in the same direction with theses. (c) There are very few books about fraud audit and forensic accounting. One of them is related to fraud audit, while the rest of them are related to forensic accounting and forensic accounting profession. We suggest extending the scope of the study and making to other countries.

This study aims to propose a practical, virtue-centric model of leadership based on Islamic principles. The structure of the Islamic leadership construct is validated through confirmatory factor analysis. Its relationship with performance and organizational commitment is examined and the mediating role of organizational commitment is assessed.

Islamic leadership model is tested using confirmatory factor analysis with data collected from employees working in the services sector in Turkey. Relationships between Islamic leadership, organizational commitment and performance are examined through a path analysis.

The factor analysis results presented a good fit for the proposed Islamic leadership model, which consists of wisdom, religiosity, justice and kindness dimensions. Regarding path analysis, findings indicated a positive relationship between Islamic leadership and job performance. Moreover, organizational commitment partially mediated the relationship between Islamic leadership and job performance.

Previous studies on Islamic leadership contain a very little number of empirical models. This study proposes a valuable empirical model of Islamic leadership consisting of moral values, spirituality, ethics and wisdom. In addition, the proposed model is supported with empirical pieces of evidence. Evidence of the partial mediating role of organizational commitment between Islamic leadership and job performance is also revealed by the study.

Fuel cells technologies are the most promising green energy technologies for diverse applications. One of the fastest growing areas is the portable electronic applications where the power range is the order of 1–100 W. For most of the portable electronic devices, rechargeable battery is the major energy source. Due to limitations like limited capacity, requirement of external power for recharge have led many researchers to look for alternative power sources to power portable electronic devices. The high energy density of fuel cells makes them very attractive alternative to batteries for portable power applications. There are a variety of fuel cell technologies being considered to replace batteries in portable electronic equipment. Direct Liquid Fuel Cells (DLFCs) have attracted much attention due to their potential applications as a power source for portable electronic devices. The advantages of DLFCs over hydrogen fed PEM fuel cells include a higher theoretical energy density and efficiency, a more convenient handling of the streams, and enhanced safety. Unlike batteries, fuel cells need not be recharged, merely refueled. This paper provides an overview on challenges of DLFCs (Direct Liquid Fuel Cells), like fuel crossover, cost, durability, water management, weight and size along with approaches being investigated to solve these challenges. Portable Fuel Cell Commercialization Targets for future and producers of portable fuel cells across the globe are also discussed in this paper.

The oil and gas construction projects are affected negatively by the drop in oil price in recent years. Thus, most engineering, procurement and construction (EPC) companies are opting to optimize the project mainly to mitigate the source of risks in construction to achieve the project expectation. Risk factors cause a threat to the project objectives regarding time, cost and quality. It is additionally a vital component in deviating from the client's expectation of productivity, safety and standards. This research aims to investigate the causes of risk in the oil and gas construction projects in Yemen.

A comprehensive literature review from various sources including books, conference proceedings, the Internet project management journals and oil and gas industry journals was conducted to achieve the objectives of this study. This initial work was predicated strictly on a literature review and the judgments of experts to develop the risk factor framework for the oil and gas construction projects in Yemen.

The authors found a few studies related to risk factors in oil and gas construction projects and shared a similar view about general construction projects. However, only a fraction of the factors accepted have included the variances of other studies on a regional basis or specific countries, such as the Yemen situation, due to the differences between the general construction industry and oil and gas industry. Moreover, the factors of these attributes were still accepted due to their applicability to the oil and gas industry, and no significant variances existed between countries. Research has indicated that 51 critical factors cause risks in the oil and gas construction projects in Yemen. Such risk factors can be divided into two major groups: (1) internal risk factors, including seven critical sources of risks, namely client, contractor, consultant, feasibility study and design, tendering and contract, resources and material supply and project management; and (2) external risk factors, including six sources of critical risk factors, namely national economic, political risk, local people, environment and safety, security risk and force-majeure-related risk factors. A risk factor framework was developed to identify the critical risk factors in the oil and gas construction projects in Yemen.

This research was limited to the oil and gas construction projects.

Practically, this study highlights the risk factors that cause a negative effect on the success of oil and gas construction projects in Yemen. The identification of these factors is the first step in the risk management process to develop strategic responses for risks and enhance the chances of project success.

The identification of risks factors that cause the failure of construction projects helps develop response strategies for these risks, thereby increasing the chances of project success reflected in the oil and gas sector, which is a main tributary of the national economy in developing countries.

This research is the pioneer for future investigations into this vital economic sector. Given the lack of resources and studies in the field of construction projects for the Yemeni oil and gas sector, the Yemeni government, oil companies and researchers in this field are expected to benefit from the results of this study. The critical risk factors specific to the oil and gas construction projects in Yemen should be further investigated with focus only on Yemen and its oil and gas industry players.