Any consensus about the effects of dihedral angle on hover rigidity of rotary-wing unmanned aerial vehicles (RW-UAVs) does not exist in the literature. There are researchers who…
Abstract
Purpose
Any consensus about the effects of dihedral angle on hover rigidity of rotary-wing unmanned aerial vehicles (RW-UAVs) does not exist in the literature. There are researchers who state that the dihedral angle has an effect on flight stability and researchers who claim the opposite. The discord stems from the different approaches of these groups to the concept of “stability,” the fact that they conduct experiments whose measurements are largely influenced by environmental conditions, and the physical assumptions are not similar. On the other hand, there is no study examining the effect of dihedral angle on the maneuverability of drones either. This study aims to analytically reveal the consequences of dihedral angles in RW-UAVs in terms of flight agility and maneuverability.
Design/methodology/approach
Dihedral angle examinations on both hover rigidity and maneuverability are carried out analytically. Equations of motions for a multicopter’s rigid body with a dihedral angle under two different conditions (zero and nonzero dihedral angles) are derived. Numerical simulations are conducted by defining the simulation parameters, and then displacement graphics for the center of mass are interpreted.
Findings
The presence of a dihedral angle makes the multicopter platforms behave like a pendulum, and this pendulum motion affects the disturbance rejection and the planar maneuver capabilities of multicopters. Since deflections can be spread to the orthonormal axes thanks to rotation about a pivot, net deflections of the geometric center may be diminished. Besides, pendulum motion eases the maneuvers with yaw rotations since the required rotation might occur without rotors’ revolution per minute changes.
Practical implications
Proposed dihedral angle implementation may enhance the hover stiffness and maneuverability capabilities of multicopters which, in turn, raise the performance of the drones.
Originality/value
This paper presents the analytical basis for the dihedral angle's effects on flight stability and agility.
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H. Murat Celik and Ugur Yankaya
The purpose of this paper is to test whether the rail transit investment in Izmir, Turkey has had positive valuation impacts on the surrounding residential properties, and to…
Abstract
Purpose
The purpose of this paper is to test whether the rail transit investment in Izmir, Turkey has had positive valuation impacts on the surrounding residential properties, and to estimate the value of travel time using relevant parameters.
Design/methodology/approach
The necessary data were collected via a survey including all real‐estate agents in the area. To test the research question, the Hedonic Price Model (HPM) is used as the research technique. The obtained parameters are also used to estimate the value of travel time.
Findings
The findings of the models has indicated that the proximity to rail stations was valued at $250‐300 per meters, and the value of travel per hour was $1.47‐1.83 on average.
Research limitations/implications
These findings should be checked with more consistent database using transaction process, and the mortgage loan rate which was not legislated at the time of study.
Practical implications
Until a mortgage loan rate is registered in turkey, the estimated parameters can be used in the cost‐benefit analysis of rail transit investments in Turkey.
Originality/value
The theoretical premise that “any improvement in accessibility will be capitalized into the land values” is tested one more time in a developing country case whose urban environment is substantially different from those of the developed world, especially the North American cities. Furthermore, a new methodology using the HPM parameters is also suggested to estimate the value of travel time.
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Mustafa Koyuncu, Ronald J. Burke, Marina Astakhova, Duygu Eren and Hayrullah Cetin
The aim of this article is to examine the relationship of service employees perceptions of servant leadership provided by their supervisors/managers and employee’s reports of…
Abstract
Purpose
The aim of this article is to examine the relationship of service employees perceptions of servant leadership provided by their supervisors/managers and employee’s reports of service quality provided to clients by their hotels.
Design/methodology/approach
Data were collected from 221 frontline employees, a 37 per cent response rate, working in four- and five-star hotels in Cappadocia, Turkey. Previously developed and validated measures of servant leadership (Liden et al., 2008) and service quality (Parasuraman et al., 1988) were used and both were found to be highly reliable in this study.
Findings
Respondents were generally young, had relatively short organizational tenure and had high school educations. Respondents having longer organizational tenures and those working in five-star hotels reported lower levels of servant leadership. Longer tenured employees, and males, rated some dimensions of service quality lower as well. Service employees reporting higher levels of servant leadership from their supervisors/managers generally indicated higher levels of service quality.
Research limitations/implications
Some limitations should be noted. First, all data were collected using respondent self-reports, raising the limited possibility of response set tendencies. Second, the sample, while reasonably large, may not be representative of all hotel employees in Turkey. Third, all properties were located in one region of Turkey and may not be representative of hotel employees in other regions of the country.
Practical implications
First, organizations could select individuals exhibiting higher levels of servant leadership potential based on indications that these individuals are interested in developing long-term relationships with staff and co-workers and in helping them become more skilled in doing their jobs. Selection can also be augmented by servant leadership training (Fulmer and Conger, 2004). Supervisors/managers could be coached to help them develop their staff and help them meet their unique goals (Raelin, 2003). Finally, workplace cultural value supportive of both servant leadership and service quality can be identified, modeled by senior level managers, supported and rewarded.
Originality/value
Most studies focus on defining and measuring servant leadership or service quality. This study investigates the relationship between servant leadership and service quality.
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Jeffrey Boon Hui Yap and Seh Vian Goh
The purpose of this paper is to explore the potential of transit-oriented development (TOD), the perceptions of buyers and the establishment of the comfortable walking distance…
Abstract
Purpose
The purpose of this paper is to explore the potential of transit-oriented development (TOD), the perceptions of buyers and the establishment of the comfortable walking distance. The literature indicates the requirement of TOD with increasing population in major cities.
Design/methodology/approach
In this study, exploratory sequential mixed methods research approach was adopted. Semi-structured interviews were conducted followed by questionnaire survey. The respondents were categorised based on their generation cohorts to further understand their acuities on TOD.
Findings
The key consideration factors when buying houses in the TOD area are as follows: amenities related to jobs and family for Baby Boomers; time saving for Generation Y; and location for Generation X, i.e. house should be conveniently located in relation to working place, school, etc. Communities in Malaysia are willing to walk for five to ten minutes (approximately 400 to 800 m).
Research limitations/implications
Future studies can be enlarged to include other major cities in Malaysia and draw comparisons with neighbouring ASEAN countries.
Practical implications
This paper provides insights to property developers, consultants and government agencies for product development. Ultimately, TOD is the innovative sustainable solution for high-density urban planning and development.
Social implications
TOD is a sustainable development concept that encourages the use of public transportation system in order to reduce private motor vehicles usage.
Originality/value
This paper emphasises the potential of TOD, explores the perceptions of different generation cohorts in relation to TOD and establishes the comfortable walking distance for Malaysian communities. It also highlights the key factors of conveniences for TOD.
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Safa Sabet, Moghtada Mobedi, Murat Barisik and Akira Nakayama
Fluid flow and heat transfer in a dual scale porous media is investigated to determine the interfacial convective heat transfer coefficient, numerically. The studied porous media…
Abstract
Purpose
Fluid flow and heat transfer in a dual scale porous media is investigated to determine the interfacial convective heat transfer coefficient, numerically. The studied porous media is a periodic dual scale porous media. It consists of the square rods which are permeable in an aligned arrangement. It is aimed to observe the enhancement of heat transfer through the porous media, which is important for thermal designers, by inserting intra-pores into the square rods. A special attention is given to the roles of size and number of intra-pores on the heat transfer enhancement through the dual scale porous media. The role of intra-pores on the pressure drop of air flow through porous media is also investigated by calculation and comparison of the friction coefficient.
Design/methodology/approach
To calculate the interfacial convective heat transfer coefficient, the governing equations which are continuity, momentum and energy equations are solved to determine velocity, pressure and temperature fields. As the dual scale porous structure is periodic, a representative elementary volume is generated, and the governing equations are numerically solved for the selected representative volume. By using the obtained velocity, pressure and temperature fields and using volume average definition, the volume average of aforementioned parameters is calculated and upscaled. Then, the interfacial convective heat transfer coefficient and the friction coefficient is numerically determined. The interparticle porosity is changed between 0.4 and 0.75, while the intraparticle varies between 0.2 and 0.75 to explore the effect of intra-pore on heat transfer enhancement.
Findings
The obtained Nusselt number values are compared with corresponding mono-scale porous media, and it is found that heat transfer through a porous medium can be enhanced threefold (without the increase of pressure drop) by inserting intraparticle pores in flow direction. For the porous media with low values of interparticle porosity (i.e. = 0.4), an optimum intraparticle porosity exists for which the highest heat transfer enhancement can be achieved. This value was found around 0.3 when the interparticle porosity was 0.4.
Research limitations/implications
The results of the study are interesting, especially from heat transfer enhancement point of view. However, further studies are required. For instance, studies should be performed to analyze the rate of the heat transfer enhancement for different shapes and arrangements of particles and a wider range of porosity. The other important parameter influencing heat transfer enhancement is the direction of pores. In the present study, the intraparticle pores are in flow direction; hence, the enhancement rate of heat transfer for different directions of pores must also be investigated.
Practical implications
The application of dual scale porous media is widely faced in daily life, nature and industry. The flowing of a fluid through a fiber mat, woven fiber bundles, multifilament textile fibers, oil filters and fractured porous media are some examples for the application of the heat and fluid flow through a dual scale porous media. Heat transfer enhancement.
Social implications
The enhancement of heat transfer is a significant topic that gained the attention of researchers in recent years. The importance of topic increases day-by-day because of further demands for downsizing of thermal equipment and heat recovery devices. The aim of thermal designers is to enhance heat transfer rate in thermal devices and to reduce their volume (and/or weight in some applications) by using lower mechanical power for cooling.
Originality/value
The present study might be the first study on determination of thermal transport properties of dual scale porous media yielded interesting results such as considerable enhancement of heat transfer by using proper intraparticle channels in a porous medium.
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Murat Selim Selvi, Aykut Pajo, Ceyda Çakir and Emre Demir
Because of competition, residential property developers use a variety of promotional tools to gain recognition and increase their market share and the demand for housing, and to…
Abstract
Purpose
Because of competition, residential property developers use a variety of promotional tools to gain recognition and increase their market share and the demand for housing, and to manage their customer relations. This study aims to examine what real estate developers did to detect the need for types of housing, and pricing and promoting housing. It also sought clues about how they manage customer relations in residential sales.
Design/methodology/approach
In this study, semi-structured interviews were conducted with real estate developers. This study has heuristic characteristics based on qualitative data. Document reviews, descriptive analysis and discourse analysis were carried out on the interview data and other sources. As purposeful sampling is generally used in qualitative studies; intensity sampling, homogeneous sampling, criterion sampling and snowball sampling were used together in this study.
Findings
The study found that real estate developers were inadequate at advertising and promoting, allocated little budget for promotion and did not use technology sufficiently. The real estate developers gave discounts at rates that did not actually desire, had to create payment plans, and as a result, they lost customers because they could not manage customer relations well.
Research limitations/implications
Interviews were conducted with 15 real estate developers who have been selling residential properties for more than 10 years in Süleymanpasa and Çorlu districts of Tekirdag. Data obtained are mostly qualitative.
Originality/value
This study aimed to determine real estate developers’ ability to implement a variety of promotional strategies and manage customer relations. Results and conclusions can offer significant clues about real estate developers with similar characteristics. Its conclusions of this study can be compared to similar studies of real estate developers in many regions of Turkey.
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Seval Kardeş Selimoğlu and Mehtap Altunel
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…
Abstract
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.
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Murat Kasimoğlu and Ali Halici
Despite legal and administrative arrangements and increase in the sensitiveness for human rights, discriminative applications are important problems in organizations, because…
Abstract
Despite legal and administrative arrangements and increase in the sensitiveness for human rights, discriminative applications are important problems in organizations, because different applications and unfair behaviors for workers lead to negative consequences for the workers and the organization. The main discrimination areas that are stated in the literature are race, language, religion, sex, ideology and physical insufficiency etc., but these subjects would differ according to the region and sector. The aim of this study is to determine the discrimination areas in higher education Institutions in Turkey and develop a scale for measuring the level of discrimination in those areas. Discrimination areas are determined by an ethnographic study in the research. Within this context, factor analysis was applied to the related questions by Varimax approach and a reliable and valid scale was obtained.
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This chapter presents findings of an ongoing project on the social construction of ethnic identity among young Kurdish immigrants living in Turkey. The chapter begins with…
Abstract
This chapter presents findings of an ongoing project on the social construction of ethnic identity among young Kurdish immigrants living in Turkey. The chapter begins with information on Kurdish culture. The second part overviews the difficult relations between the Turkish state and Kurds since establishment of the Republic in 1923. The third section describes the education system in the country and in Istanbul specifically. Historical ties between the Istanbul and Kurdish culture are also mentioned. The chapter closes with research that focuses on problems of Kurdish educational experiences in Turkey and preservation of their cultural identity in Istanbul. The study shows that on the one hand public education is perceived by the Kurds in Turkey as a discriminatory entity but on the other hand nonpublic educational opportunities in Istanbul help Kurdish migrants preserve and practice their cultural identity.
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Yanfei Yang, Xiaobo Wang, Sen Mei, Xing Zhu, Shiqiang Chen, Peng Xiong, Zhihai Hu, Kun Xiong and Dong Song Yuan
The purpose of this paper is to investigate the tribological performance and mechanisms of BN/calcium borate nanocomposites (BCBNs) as additives in lubricating oil.
Abstract
Purpose
The purpose of this paper is to investigate the tribological performance and mechanisms of BN/calcium borate nanocomposites (BCBNs) as additives in lubricating oil.
Design/methodology/approach
BCBNs were prepared by heterogeneous deposition method. And the morphology and structure of samples were analysed by transmission electron microscopy, Fourier transform infrared spectra and X-ray powder diffraction pattern. The maximum non-seizure load (PB) of samples was tested using four-ball friction tester. The average friction coefficients and wear tracks were obtained. In addition, tribological mechanism was also investigated using optical microscope, energy dispersive spectroscopy and X-ray photoelectron spectroscope.
Findings
It was found that the nanocomposites present core-shell nanostructure with the thickness of shell around 12 nm and the diameter of particles 100-200 nm, and tribological tests indicate that the PB value of BCBNs was increased by 113 per cent, whereas the average friction coefficient was decreased by 23.6 per cent and the bloom’s wear area was also decreased by 25.2 per cent.
Originality/value
This paper involves investigation on tribological properties and mechanism of the BCBNs with core-shell structure.