Karabük Üniversitesi Kurumsal Akademik Arşivi
DSpace@Karabük, Karabük Üniversitesi tarafından doğrudan ve dolaylı olarak yayınlanan; kitap, makale, tez, bildiri, rapor, araştırma verisi gibi tüm akademik kaynakları uluslararası standartlarda dijital ortamda depolar, Üniversitenin akademik performansını izlemeye aracılık eder, kaynakları uzun süreli saklar ve telif haklarına uygun olarak Açık Erişime sunar.
Güncel Gönderiler
The effect of PWHT on the mechanical properties of HHA 500 armor steel welds
(FEB 2025) Ertek Emre, Hayriye; Kece, Serkan; Kacar, Ramazan; Nohutcu, Samet
Armor steels are produced to protect against any explosions and armed attacks. In addition, high hardness armor (HHA) steels have excellent ballistic properties due to their hardness and strength. Choosing the correct welding method and providing optimum heat input when joining armor steels is very important in order to obtain the desired properties. Additionally, unwanted residual stresses occur after welding. It can be relieved by post-weld heat treatments (PWHT). This research aims to investigate the effect of PWHT on the mechanical properties and microstructure of Bisalloy HHA500 armor steel welded with gas metal arc welding (GMAW). The Bisalloy HHA500 series armor steels were joined with the automated GMAW method at optimized welding parameters through preliminary experimental tests. After welding processes, PWHT was applied at 650°C for 1 hour. In order to determine the mechanical properties of both as-welded and PWHT joints, tensile, bending, and Charpy-notch impact tests were performed. The microstructure investigation and hardness measurements were carried out. As a result of PWHT, an increase in the Charpy-notch impact strength by 16% was detected. © IMechE 2025.
Task-Based Language Teaching and Learning Process Through Web 2.0 Tools
(2025) Tosuncuoglu, Irfan
The individuals are in need of learning at least one foreign language as foreign language skills are very important for them. The methods approaches and techniques have been tried in language teaching and learning activities in order to reach goals in the quickest and most reliable way. It is denoted that task-based method is a reliable method in teaching and learning foreign languages. In task-based method, mental learning is transformed into observable behaviors and it is ensured that the learners does not memorize information, but rather they reinforce their mental structures in mind while practically performing the given task. On the other hand in the Web 2.0-based learning environment, it is important to design environments that highlight features such as problem solving, transferring what they have learned to the problem, and using time effectively by creating problem situations that learners can encounter in real life with a task-based method. The web was seen as a large knowledge bank where static structures were used to present information, but today it is seen as an unlimited environment that includes more dynamic and interactive processes. In this regard in order to determine the fourth grade students' perceptions about the use of web 2.0 tools in task-based language learning students of Karab & uuml;k University of Department of English Language and Literature. An interview was conducted with four learners who planned to be teachers of English in the future. At the end of the interview their responses classified and evaluated. They took part in interviews voluntarily.
Device to Prevent Tip-Over of Indoor Furniture
(MAY 2025) Ozcan, Suleyman; Ozcan, Cemal; Yildirim, Mehmet Nuri
This study proposes an innovative product design to enhance the safety of indoor furniture. Currently, furniture presents safety concerns due to various factors such as improper placement, excessive loads, and environmental influences. The most prominent of these safety issues is furniture tip-over. Therefore, product designs aimed at preventing tip-over have been developed to ensure safety in indoor environments and avert potential accidents. In the initial phase of the study, the factors contributing to tip-over in a standard cabinet were investigated: the height of force application, leg diameter, leg length, leg's position on the bottom panel, and the furniture's load status. In the second phase, designs to prevent tip-over were developed. Following prototype production stages, the developed product was mounted on the cabinet, and experiments incorporating product variables and other variations were conducted. The results indicate that the effectiveness of the developed tip-over prevention product varies depending on usage, with its impact on preventing tip-over ranging between 17.5% and 54.3%. These findings suggest that the designed product can significantly enhance indoor safety and offers a potential alternative solution for preventing furniture tip-over.
Investigation of the freeze-drying characteristics of scrambled eggs
(FEB 2025) Acar, Bahadir; Aydin, Murat
Eggs are one of the wealthiest protein products and have been widely used in industrial food preparation and daily cooking. Freeze-drying is a novel and promising method for dehydrating products containing temperature-sensitive ingredients to achieve extended shelf life, high quality, and excellent texture. The ice form of water is extracted from the material under low pressure by sublimation, and the lower temperature permits the highest control of the nutrient and bioactive compound as well. This study presents experimentally the determination of the freeze-drying process with scrambled eggs. The kinetic results of the drying process were adapted to the total of eight various empirical drying models in order to define the suitable model representing weight loss through the freeze-drying process. Among the drying models, it has been determined that Logarithmic drying model was the most proper drying model with a determination coefficient of 0.9816, a reduced chi-square of 2.74×10-3, and a root mean square error of 0.05241. The effective diffusivity was found to be as 4.8454×10-10 m2s-1.
Dynamic Response Analysis and Active Vibration Control of the Smart Sandwich Composite Plate With FGM Core Layers and MIMO FGPM Actuators and Sensors
(MAR 2025) Aktas, Kerim Gokhan; Esen, Ismail
This article deals with the dynamic response analysis and active vibration control of the smart functionally graded material (FGM) composite core plate with FG piezoelectric material (FGPM) surface actuators and sensors. Considering a power law distribution, the mechanical and electrical material characteristics of the FGM and FGPM layers change continually along the thickness plane. The finite element method (FEM) and the first-order shear deformation theory (FSDT) are utilized in the modeling process for the FGM and FGPM layers. In the dynamic analysis, the dynamic response of the sandwich structure under the impact of sinusoidally distributed step load and the corresponding sensor voltage is obtained. To ensure that the simulations are accurate, the findings are compared with previously published research. To analyze the control efficiency of FGPM sensors and actuators on the FGM host structure, the linear quadratic regulator (LQR) controller is utilized. The sandwich structure is considered a multiple-input multiple-output system (MIMO), so sensors and actuators are placed at different locations on the plate surface. The modal strain energy method is utilized to find the appropriate location of the FGPM layers. According to the results of the analysis, it has been determined that piezoelectric material coefficients as well as mechanical properties are extremely important for obtaining optimum control performance from FGPM sensors and actuators. In addition, it is emphasized that active vibration control of FGM plates can be performed effectively with the proper selection of sensors and actuators and their accurate distribution on the plate. These results are expected to contribute to micro-electro-mechanical system (MEMS) sensor and actuator applications, soft robotics applications, and vibration protection and vibration damping applications of nanostructures.
