Hittite Journal of Science and Engineering

Journal Information
ISSN / EISSN : 2149-2123 / 2148-4171
Published by: Hitit University (10.17350)
Total articles ≅ 261

Latest articles in this journal

Erhan Cetin, Cengiz Baykasoglu
Hittite Journal of Science and Engineering, Volume 9, pp 151-158; https://doi.org/10.17350/hjse19030000266

Thin-walled tubes are widely used as passive energy-absorbing structures in a variety of industries. These structures are typically filled with lightweight materials to improve their energy absorption capabilities. At this point, additive manufacturing technology offers a great chance to researchers for the production of novel filler structures to increase the crashworthiness performance of thin-walled tubes. In the current work, additive manufacturable body-centered cubic (BCC) lattice structures are suggested as filling materials for tubes, and the bending response of these structures are investigated under transverse loads via finite element modeling approach. The aspect ratio and strut diameter are considered as design parameters, and three-point bending simulations are conducted to understand transverse load bearing behaviors of the structures. Different loading offsets are also taken into account for three-point bending simulations. The numerical results revealed that the BCC lattice structures used as filler materials significantly increase the energy absorption performance of thin-walled tubes due to synergetic interactions. In particular, the results showed that the hybrid tubes can absorb up to 84% more energy than the empty tubes, while the crush force efficiency of these structures is up to 42% higher compared to the empty tubes. The present study also showed that the transverse crushing characteristics of tubes can be considerably improved by suitable selection of the design parameters. These primary outcomes reveal that the proposed lattice structures can be considered as a potential alternative to traditional filler materials for enhancing the bending response of thin-walled tubes under transverse loading.
Levent Kartal
Hittite Journal of Science and Engineering, Volume 9, pp 145-150; https://doi.org/10.17350/hjse19030000265

In this study, calciothermic single phase iron boride(Fe2B) production was investigated in a scalable molten salt system, starting from inexpensive, easily accessible oxide materials. First, the formation of Fe2B was examined in detail in the light of thermodynamic data and literature. After, effects of CaO amount (0-10 wt.%) and time (30-60 min) on particle synthesis were investigated under at constant 3.0 V cell voltage and 1273 K temperature. It was determined that the average current increased continuously with the increase in the amount of CaO, and the current efficiency increased up to 7% by weight of CaO. After the CaO ratio was determined, the effect of the electrolysis duration was examined. In durations experiments, it has been observed that, in 30 minutes’ duration, the particles are composed of Fe, Fe2B and FeB, and by increasing the experiment time to 60 min, single-phase Fe2B particles are obtained. The magnetic properties of the single-phase Fe2B particles obtained at the end of the experiment period of 60 minutes were investigated by VSM. The saturation magnetization, permanent magnetization and coercivity values of the Fe2B particles were determined as 90.718 emu/g, 33.311 Oe, 1.684 emu/g, respectively.
İzzet Paruğ DURU
Hittite Journal of Science and Engineering, Volume 9, pp 103-110; https://doi.org/10.17350/hjse19030000260

Defect-induced magnetic phases of 2D and 3D MnB were discussed. The exciting ferromagnetic behavior of MnB MBene is particularly tracked, including high-rated Mn defects via ab-initio calculations and Monte Carlo simulations. Ground state solution was achieved through GGA in PBESol scheme resulting in magnetic state and moments of Mn ions including the density of states around Fermi level. Magnetic susceptibility and magnetization behavior related to temperature was obtained through Monte Carlo simulations based on the Heisenberg model applying Metropolis criteria. The authors focused on controlling the Curie temperature considering the location of Mn defects. The coexistence of the various defect locations opened a realistic window to estimate Curie temperature consistent with experimental values. Exchange energies of 2D MnB different defect locations quite differ from each other. In addition, magnetic moments of the sheet material were found to be higher than 3D bulk MnB.
Mustafa Güven Gök, Ömer Cihan
Hittite Journal of Science and Engineering, Volume 9, pp 83-88; https://doi.org/10.17350/hjse19030000258

Aircraft are subjected to an impact load during landing. This situation becomes more important for unmanned aerial vehicles that are remotely controlled and must serve in extreme conditions. Because the landing gear should absorb this impact load as much as possible and prevent damage to the unmanned aerial vehicle body and its components. In this study, a landing gear design has been developed for unmanned aerial vehicles that can absorb more impact load during landing. Numerical analyzes were performed to determine the fatigue life and the maximum impact load that the developed design can withstand. In addition, a conventional landing gear was modeled and the results were compared. The properties of 7075-T6 Aluminum alloy were used as the landing gear material. As a result of the finite element analyzes made with Ansys software, it has been understood that the newly designed landing gear can absorb more energy than the conventional landing gear. It has also been determined that it can be used at values up to 3700N impact load.
Mustafa Serhat Ekinci, Abdurrahman Akman
Hittite Journal of Science and Engineering, Volume 9, pp 125-132; https://doi.org/10.17350/hjse19030000263

Many hazardous substances are produced, stored and transported in the chemical industry. With the release of these hazardous substances as a result of any uncontrolled development, fire, explosion and toxic spread may occur depending on the nature of the chemical substance. This, in turn, can harm employees, people around, the environment and the economy. In this study, the release of ammonia, which has many uses, has been investigated. Ammonia is a flammable and highly toxic substance. As a result of the accidental releasing of ammonia, a fire event can be prevented by measures such as not keeping the ignition sources in the environment. However, although its ignition is prevented, it can cause harm to the people and environment due to its highly toxic nature. Knowing how much area it affects after spreading will shed light on the measures to be taken to prevent or reduce the damages that may occur. In this study, the toxicity of ammonia was taken into account, and the effect of storage temperature on the size of the toxic area to be formed was investigated. This effect was examined with Areal Locations of Hazardous Atmosphere (ALOHA) and DOW’s Chemical Exposure Index (DOW CEI) methods, and the results obtained with both methods were compared.
Yıldıran Yilmaz, Selim Buyrukoğlu
Hittite Journal of Science and Engineering, Volume 9, pp 73-82; https://doi.org/10.17350/hjse19030000257

Internet of Things that process tremendous confidential data have difficulty performing traditional security algorithms, thus their security is at risk. The security tasks to be added to these devices should be able to operate without disturbing the smooth operation of the system so that the availability of the system will not be impaired. While various attack detection systems can detect attacks with high accuracy rates, it is often impossible to integrate them into IoT devices. Therefore, in this work, the new DDOS detection models using feature selection and learning algorithms jointly are proposed to detect DDOS attacks, which is the most common type encountered by IoT networks. The data set consisting of 79 features in total created for the detection of DDOS attacks was minimized by selecting the two most significant features. Evaluation results confirm that the DDOS attack can be detected with high accuracy and less memory usage by the base models compared to complex learning methods such as bagging and boosting models. As a result, the findings demonstrate the feasibility of the base models, for the IoT DDOS detection task, due to their application performance.
Özge Akyazi, Şule Coşkun CEVHER
Hittite Journal of Science and Engineering, Volume 9, pp 65-72; https://doi.org/10.17350/hjse19030000256

Asthma, an important public health problem, is a common, potentially serious, medical condition in children, adults and pregnant women. The aim of this study is to investigate the effects of the combined use of thymoquinone and carob on liver tissue oxidative events, following the experimental asthma model. 18 male albino wistar rats were divided into 3 groups as: the control group, the experimental asthma group and treated group (A+TQ+C). In the asthmatic groups, ovalbumin and alum were given intraperitoneally on the 0 and 14th days, and sensitized by inhalation on the 21st, 22nd and 23rd days. In the next 5 days, thymoquinone and carob were given to the group to be treated by intragastric gavage method. In all experimental groups, glutathione (GSH), ascorbic acid (AA), malondialdehyde (MDA) and nitric oxide (NOx) levels were measured spectrophotometrically to evaluate the oxidant-antioxidant status in the liver tissue of rats. While liver tissue GSH and AA levels increased, NOx levels were found to decrease following thymoquinone and carob administration. However, MDA levels, which are the indicator of lipid peroxidation, were found to be statistically significantly increased in the treated group (p
Hasan Akman, Ali Emre Turgut, Hakan Çalişkan
Hittite Journal of Science and Engineering, Volume 9, pp 27-36; https://doi.org/10.17350/hjse19030000252

In this study, the preliminary design of an in-flight refueling door mechanism is performed. A systematic design methodology is introduced and used in the design of the refueling door mechanism. The design is divided into two sub-functions: door opening and actuation. Nine different mechanism concepts are created for the door opening function and eight different concepts are created for the actuation function. Pugh decision matrix method is used to evaluate and select the most feasible options. Six experienced engineers scored the option set, resultantly two concepts for the door opening and three concepts for the actuation sub-function are selected. Kinematic synthesis of these concepts is performed and used to determine the upper and lower bounds during optimization. Kinematic and force analysis of the concepts are performed and utilized for the constraints and cost function calculations of the optimization algorithm. Multi-objective Genetic Algorithm optimization technique is used to optimize the parameters of the selected mechanisms. The best mechanism for each sub-function is selected and combined to reach the final design. It was shown that through optimization, the required input torque decreased approximately 20% for the door opening mechanism and the required input force decreased approximately 42% for the actuation mechanism when compared to the graphical synthesis results.
Simge Varlik, Gülşen Bayrak, Işık Perçin Demirçelik, Aybuke A. Isbir Turan
Hittite Journal of Science and Engineering, Volume 9, pp 37-44; https://doi.org/10.17350/hjse19030000253

With the rapid and alarming spread of the SARS-Cov-2 (Covid-19) virus from the coronavirus family, it was necessary to take serious measures in China at the end of 2019, in the world as of March 2020. The efforts to prevent this global epidemic have started with the legal measures taken by the countries in this regard and the warnings of the World Health Organization (WHO) that the epidemic should be taken seriously. In this process, the success of the use of masks and the use of alcohol-based hand sanitizer in preventing the disease has been evaluated and approved by scientists. In terms of the effectiveness of hand sanitizers, it is seen that the main components are ethyl alcohol and isopropyl alcohol, which are alcohol derivatives. In this study, 11 commercially purchased hand sanitizer components were identified and listed by Headspace gas chromatography-mass spectroscopy (HS-GC-MS) and their antibacterial activities were studied. Hand sanitizers containing alcohol derivatives were used in the study. As a result of this study, it was observed that 4 out of 11 commercial hand sanitizers were not suitable for the final concentration values of hand sanitizer determined by the World Health Organization (accepted as 80%(v/v) for alcohol derivatives). Apart from this, hand sanitizers numbered 5 and 9 did not show antibacterial properties against E.coli and hand sanitizers numbered 1 and 10 did not show antibacterial properties against S.aureus. This situation shows that the standards of hand sanitizers should be controlled with much more stringent rules.
Zekeriya Balli, Mehmet Salih Ağirtaş, Ali Arslantas
Hittite Journal of Science and Engineering, Volume 9, pp 19-25; https://doi.org/10.17350/hjse19030000251

The tetra substituted Zn(II) phthalocyanine complex having the dicyanophenoxy)-3-methoxybenzoic acid group had been obtained from 4-(3, 4-dicyanophenoxy)-3-methoxybenzoic acid and analyzed with the application of FT-IR, NMR, UV/Vis techniques in compliance with reported literature. The interacting property of Pc4 by CT-DNA was examined with absorption bands, emission titrations, melting temperature, viscosity, and gel electrophoresis procedures. The obtained findings from these techniques demonstrated that the complex containing the dicyanophenoxy)-3-methoxybenzoic acid binds to the DNA by means of intercalation attachment mechanisms.
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