Mustafa Kaya and Munir Ali Elfarra
The critical Mach number, lift-to-drag ratio and drag force play important role in the performance of the wings. This paper aims to investigate the effect of taper stacking, which…
Abstract
Purpose
The critical Mach number, lift-to-drag ratio and drag force play important role in the performance of the wings. This paper aims to investigate the effect of taper stacking, which has been used to generalize wing sweeping, on those parameters.
Design/methodology/approach
The results obtained are based on steady-state turbulent flowfields computations. The baseline wing is ONERA M6. Various wing planforms are generated by linearly or parabolically varying the spanwise stacking location. The critical Mach number is determined by changing the freestream Mach number for a fixed angle of attack. On the other hand, the analysis of the drag force is carried out by changing the angle of attack to keep the lift force constant.
Findings
By changing the stacking location, the critical Mach number and the corresponding lift-to-drag ratio have increased by around 7 and 3%, respectively. A reduction of 12.8% in total drag force has been observed in one of the analyzed cases. Moreover, there exist some cases in which the values of drag reduce significantly while the lift is the same.
Practical implications
The results of this new stacking approach have implied that the drag force can be decreased without decreasing the lift. This outcome is valuable for increasing the range and endurance of an aircraft.
Originality/value
This work generalizes wing sweeping by modifying the taper stacking along the span. In literature, wing sweep is enhanced using segmented stacking of taper distribution. The present study is further enhancing this concept by introducing continuous stacking (infinite number of stacking segments) for the first time.
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Burak Dam, Tolga Pirasaci and Mustafa Kaya
Environmental and operational restrictions increasingly drive modern aircraft design due to the growing impact of global warming on the ecology. Regulations and industrial…
Abstract
Purpose
Environmental and operational restrictions increasingly drive modern aircraft design due to the growing impact of global warming on the ecology. Regulations and industrial measures are being introduced to make air traffic greener, including restrictions and environmental targets for aircraft design that increase aerodynamic efficiency. This study aims to maximize aerodynamic efficiency by identifying optimal values for sweep angle, taper ratio, twist angle and wing incidence angle parameters in wing design while keeping wing area and span constant.
Design/methodology/approach
Finding optimal wing values by using gradient-based and evolutionary algorithm methods is very time-consuming. Therefore, an artificial neural network-based surrogate model was developed. Computational fluid dynamics (CFD) analyses were carried out by using Reynolds-averaged Navier–Stokes equations to create a properly trained data set using a feedforward neural network.
Findings
The results showed how a wing could be optimized by using a CFD-based surrogate model. The two optimum results obtained resulted in increases of 10.7397% and 10.65% in the aerodynamic efficiency of the baseline design ONERA M6 wing.
Originality/value
The originality of this study lies in the combination of sweep angle, taper ratio, twist angle and wing incidence angle within the scope of wing optimization calculations.
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Tuğberk Kaya, Mustafa Sağsan, Tunç Medeni, Tolga Medeni and Mete Yıldız
The manner in which people, businesses and governments perform is changing because of the spread of technology. Digitalization of governments can be considered a necessity as we…
Abstract
Purpose
The manner in which people, businesses and governments perform is changing because of the spread of technology. Digitalization of governments can be considered a necessity as we are now entering the era of the Internet-of-Things. The advantages and disadvantages of electronic governments have been examined in several research studies. This study aims to examine the attitudes of decision-makers towards e-government. The research aims are as follows: to determine the problems related with e-government usage, to establish the factors which decrease the usage of e-government services and to propose recommendations for the effective application of e-government practices.
Design/methodology/approach
Qualitative research has been used for the study. Participants were chosen by the snowball sampling method, and face-to-face in-depth interviews were conducted with all decision-makers. In-depth interviews are more efficient and enable the acquisition of better qualitative information, in-depth knowledge and statistics, as the distance between the interviewer and interviewee is reduced (Stokes and Bergin, 2006). Questions asked can be categorized under two sections, where the questions in the first section are related to the decision-maker’s management style/managerial proposition, and in the second section, technological questions are asked in terms of the preferred communication method and the decision-makers’ attitudes towards e-government practices.
Findings
Decision-makers perceive electronic government to be important, while the level of importance is observed to be different among the decision-makers. Chronic problems exist in many countries, such as nepotism, where the decision-makers have conflicting arguments about e-government and the resulting effect on nepotism. Furthermore, the study also indicates that decision-makers are aware of the importance of mobile government, although they acknowledge that more time is required, as their country is still developing. Electronic voting is also perceived to be important, although the decision-makers believe that security and privacy issues need to be solved before related projects can be initiated.
Originality/value
This research can be a benchmark study for the decision-makers of small island developing states by means of e-government. The impediments preventing the effective application of e-government practices are also discussed in the study. This study will be useful to highlight the triggers and obstacles for e-government development in the context of a developing country. Internet penetration has increased significantly since the 2000s, and therefore, decision-makers need to consider the shift in citizens’ behaviour, such as the high usage of smartphones and the emergence of the Internet-of-Things (Kaya and Bicen, 2016; Kumar et al., 2017).
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Safak Kaya, Esref Arac, Fethiye Akgul, Senol Comoglu, Sehmuz Kaya, Songul Araç, Yesim Yildiz, Seyit Ali Buyuktuna, Bircan Kayaaslan, Emine Parlak, Birol Baysal, Faruk Karakecili, Elif Zelal Balik, Ali Akkoç, Kevser Ozdemir, Seyhmus Kavak, Suat Ali Dogan, Emrah Günay, Semsi Nur Karabela, Mehmet Cabalak, Yasemin Cag, Veli Avci, Yasemin Durdu, Zehra Kaya, Damla Kilic, Halis Yerlikaya, Hüseyin Tarakçı, Osman Mentes, Ayse Sağmak Tartar, Adem Kose, Omer Faruk Alakus, Ulas Aktas, Halil Komek and Selcuk Aksoz
This paper aims to determine the knowledge and attitudes of the physicians regarding human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS), to emphasize…
Abstract
Purpose
This paper aims to determine the knowledge and attitudes of the physicians regarding human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS), to emphasize that these patients exist and they will exist in the future and to raise awareness so as to prevent that their rights to treatment are revoked.
Design/methodology/approach
The survey was conducted via a link sent through an online system. Random physicians from 81 cities of the country were invited to the survey. The survey has 41 questions regarding knowledge and attitudes in total, including epidemiological information such as age, gender and title.
Findings
A total of 3,107 physicians has voluntarily participated in the study. In total, 2,195 (70.7%) are internal physicians and 912 (29.3%) are surgical physicians among the participant physicians. In total, 1,452 (46.7%) of the participants are specialist physicians, 608 (19.6%) of the participants are practising physician and the rest of it is physician assistants, academicians and dentists, respectively.
Originality/value
In this study, it has been found out that the physicians have a lack of knowledge on HIV/AIDS and they adopt a discriminatory attitude towards HIV-positive persons. HIV-positive patients who are exposed to discrimination and scared of being uncovered refrain from applying to hospitals for treatment, which puts public health into jeopardy due to the high viral load and these patients are faced with difficulties in coping with both medical and emotional load of the disease.
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Mustafa Tolga Tolga Yavuz and İbrahim Özkol
This study aims to develop the governing differential equation and to analyze the free vibration of a rotating non-uniform beam having a flexible root and setting angle for…
Abstract
Purpose
This study aims to develop the governing differential equation and to analyze the free vibration of a rotating non-uniform beam having a flexible root and setting angle for variations in operating conditions and structural design parameters.
Design/methodology/approach
Hamiltonian principle is used to derive the flapwise bending motion of the structure, and the governing differential equations are solved numerically by using differential quadrature with satisfactory accuracy and computation time.
Findings
The results obtained by using the differential quadrature method (DQM) are compared to results of previous studies in the open literature to show the power of the used method. Important results affecting the dynamics characteristics of a rotating beam are tabulated and illustrated in concerned figures to show the effect of investigated design parameters and operating conditions.
Originality/value
The principal novelty of this paper arises from the application of the DQM to a rotating non-uniform beam with flexible root and deriving new governing differential equation including various parameters such as rotary inertia, setting angle, taper ratios, root flexibility, hub radius and rotational speed. Also, the application of the used numerical method is expressed clearly step by step with the algorithm scheme.
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Erdogan’s unexpected about-turn on Ataturk.
Details
DOI: 10.1108/OXAN-DB226093
ISSN: 2633-304X
Keywords
Geographic
Topical
Six million Iraqis were displaced during the Iraq-Daesh War, and although many have returned to their communities, there remain approximately 1.3 million internally displaced…
Abstract
Six million Iraqis were displaced during the Iraq-Daesh War, and although many have returned to their communities, there remain approximately 1.3 million internally displaced persons (IDPs) across the country. Today, approximately 25% of IDP children in Iraq are out of school (REACH, 2020). This study foregrounds the voices and family histories of IDPs when navigating educational access and makes a methodological argument for the need for increased qualitative research in post-conflict settings. Using the conceptual framework of navigation, the author presents displaced persons as agentic, dynamic people with lived histories, present realities, and imagined futures which inform their journey through the education system. Semi-structured interviews with 16 IDPs who identified as parents or caregivers were conducted virtually. Displaced Iraqis value education for different reasons, ranging from basic literacy to employment to societal improvement. In doing so, the author challenges the barrier-dominant framework through which IDP educational access is often understood and nuanced with a temporal lens which requires us to identify IDPs as (1) persons capable of making choices for themselves, (2) givers as well as receivers, and (3) persons who aspire to goals beyond basic survival.
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Mustafa Soylak, Nurseda Karagöz Gökçe and Eyüp Sabri Topal
The purpose of this paper is to determine the impact level of parameters affecting wing design at low speeds using Taguchi method.
Abstract
Purpose
The purpose of this paper is to determine the impact level of parameters affecting wing design at low speeds using Taguchi method.
Design/methodology/approach
Using brain storming approach airfoil shape, wing angle of attack and Reynolds number are determined as important wing design parameters. Most important parameters over these parameters are determined using Taguchi method. The lift-to-drag ratio (CL/CD ratio) is chosen as the performance criterion and L8 orthogonal index is chosen as experimental study scheme for this study.
Findings
Experimental results are examined using Taguchi method. After making experiments and also analyses, Reynolds number is found as the most important and identifier parameter for aircraft wing design.
Practical implications
Taguchi method makes the experimental design for experimental studies. This method reduces the number of experiments substantially using orthogonal indices while keeping effects of uncontrolled parameters to a minimum. Reduction in number of experiments helps save time and also cost.
Originality/value
In this study, with less number of experiments, the most important parameter for aircraft wing design is determined. Moreover, with less number of experiments, not only is time saved but the design stage is also made faster.