Welcome to the Open Access System!
OpenAccess@KU is the Academic Open Access System of Kastamonu University. It was established in June 2014 to digitally store and open access the academic outputs of Kastamonu University in international standards. OpenAccess@KU includes academic outputs such as articles, presentations, thesis, books, book chapters, reports produced within the body of Kastamonu University.
Kastamonu Üniversitesi Akademik Arşivi Creative Commons Alıntı-GayriTicari-Türetilemez 4.0 Uluslararası Lisansı ile lisanslanmıştır.
Recent Submissions
Impact of rice husk ash on physico-mechanical, durability and microstructural features of rubberized lightweight geopolymer composite
(Elsevier Ltd, 2024) Zeyad, A.M.; Bayraktar, O.Y.; Tayeh, B.A.; Öz, A.; Özkan, İ.G.M.; Kaplan, G.
This study investigates the effects of incorporating rice husk ash (RHA) on the characteristics of lightweight geopolymer concrete (LWGC), which includes waste tire aggregate (WTA). This study utilized RHA to replace 15 % of ground blast furnace slag (GBFS) in LWGC. The LWGC also included WTA as a partial substitute for pumice aggregate, with varying rates of 10 %, 25 %, and 50 % by volume. In addition, curing temperatures of 75 °C and 100 °C were utilized for 3 h following the casting process. 16 LWGC blends were created, each with a dry density below 1800 kg/m3. To study the features of hardened LWGC, various tests included apparent porosity, water absorption, capillary water absorption, dry density, compressive and flexural strength. In addition, freezing and thawing cycles (20, 40, and 60 cycles) and elevated temperatures of 250 and 500 °C affect compressive strength and density loss in addition to examining the thermal conductivity coefficient and morphological imaging by SEM on microscopic structure. The results showed that adding 15 % RHA as a partial replacement for GBSF led to a decrease in the density of hardened concrete to about 1561 kg/m3. At the same time, the compressive strength decreased to 24 and 21 MPa for the samples subjected to 75 and 100 °C heat treatments, respectively. Including 15 % RHA also reduced the thermal conductivity coefficient to 0.978 W/mK. Regarding the inclusion of WTA as a substitute for pumice aggregate, it led to a decrease in density and compressive strength as the replacement rate increased. In addition, the thermal conductivity coefficient decreases to its lowest level when WTA replaces 50 % of the pumice.
A technique of a "lab-on-a-chip" for developing a novel biosensor in viewpoint of health-care (PHC) applications and biological regulator sensors
(2024.01.01) Monajjemi, M.; Mollaamin, F.
PurposeRecently, powerful instruments for biomedical engineering research studies, including disease modeling, drug designing and nano-drug delivering, have been extremely investigated by researchers. Particularly, investigation in various microfluidics techniques and novel biomedical approaches for microfluidic-based substrate have progressed in recent years, and therefore, various cell culture platforms have been manufactured for these types of approaches. These microinstruments, known as tissue chip platforms, mimic in vivo living tissue and exhibit more physiologically similar vitro models of human tissues. Using lab-on-a-chip technologies in vitro cell culturing quickly caused in optimized systems of tissues compared to static culture. These chipsets prepare cell culture media to mimic physiological reactions and behaviors.Design/methodology/approachThe authors used the application of lab chip instruments as a versatile tool for point of health-care (PHC) applications, and the authors applied a current progress in various platforms toward biochip DNA sensors as an alternative to the general bio electrochemical sensors. Basically, optical sensing is related to the intercalation between glass surfaces containing biomolecules with fluorescence and, subsequently, its reflected light that arises from the characteristics of the chemical agents. Recently, various techniques using optical fiber have progressed significantly, and researchers apply highlighted remarks and future perspectives of these kinds of platforms for PHC applications.FindingsThe authors assembled several microfluidic chips through cell culture and immune-fluorescent, as well as using microscopy measurement and image analysis for RNA sequencing. By this work, several chip assemblies were fabricated, and the application of the fluidic routing mechanism enables us to provide chip-to-chip communication with a variety of tissue-on-a-chip. By lab-on-a-chip techniques, the authors exhibited that coating the cell membrane via poly-dopamine and collagen was the best cell membrane coating due to the monolayer growth and differentiation of the cell types during the differentiation period. The authors found the artificial membrane, through coating with Collagen-A, has improved the growth of mouse podocytes cells-5 compared with the fibronectin-coated membrane.Originality/valueThe authors could distinguish the differences across the patient cohort when they used a collagen-coated microfluidic chip. For instance, von Willebrand factor, a blood glycoprotein that promotes hemostasis, can be identified and measured through these type-coated microfluidic chips.
PV Cells and Modules Parameter Estimation Using Coati Optimization Algorithm
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Elshara, R.; Hançerlioğullari, A.; Rahebi, J.; Lopez-Guede, J.M.
In recent times, there have been notable advancements in solar energy and other renewable sources, underscoring their vital contribution to environmental conservation. Solar cells play a crucial role in converting sunlight into electricity, providing a sustainable energy alternative. Despite their significance, effectively optimizing photovoltaic system parameters remains a challenge. To tackle this issue, this study introduces a new optimization approach based on the coati optimization algorithm (COA), which integrates opposition-based learning and chaos theory. Unlike existing methods, the COA aims to maximize power output by integrating solar system parameters efficiently. This strategy represents a significant improvement over traditional algorithms, as evidenced by experimental findings demonstrating improved parameter setting accuracy and a substantial increase in the Friedman rating. As global energy demand continues to rise due to industrial expansion and population growth, the importance of sustainable energy sources becomes increasingly evident. Solar energy, characterized by its renewable nature, presents a promising solution to combat environmental pollution and lessen dependence on fossil fuels. This research emphasizes the critical role of COA-based optimization in advancing solar energy utilization and underscores the necessity for ongoing development in this field.
The Perception of Africa in Ottoman Magazines of the 2nd Constitutional Period
(Abidin Temizer, 2024) Yilmaz, M.
The Ottoman Empire resided in the African continent for nearly 400 years. The Ottoman Empire, which extended its borders to the southern shores of the Mediterranean and made its influence felt from there to the interior of Africa, did not encounter any significant difficulties because this geography was largely Muslim. Africans also respected the Ottoman sultans, who were representatives of the caliphate. However, with the geographical discoveries that started in Western Europe, the previously unknown African geography became known to Westerners. Within the scope of Western Europe's economic activities which would lead to imperialism, the African continent constituted a source of human and underground wealth to be exploited. The imperial rise of the West progressed in parallel with the exploitation of the continent of Africa. The power that could resist the imperial states in Africa was the Ottoman Empire. Therefore, these states fought against the Ottoman Empire to conquer Africa. By 1911, Tripoli, which was the last Ottoman territory in Africa, was attacked by Italy and the Ottoman Empire was forced to retreat from Africa. During such a period, magazines published in the Ottoman Empire drew attention to the developments in Africa. Islamic motifs were used as much as possible to increase the motivation of the people in the ongoing Tripoli War. These magazines focused on how imperialism could be resisted by emphasizing the political, economic and religious goals of the imperialist Western states on the continent. Issues requiring self-criticism about the Ottoman Empire and the Islamic world in general were also mentioned. This study examines the interest of the Ottoman Empire in Africa between 1908 and 1914 through the magazines of the period.
CEO research in hospitality and tourism: a systematic literature review and future outlook
(2024.01.01) Saydam, M.B.; Arici, H.E.; Koseoglu, M.A.
Although the literature on hospitality and tourism (H&T) emphasizes the role of the chief executive officer (CEO) in ensuring a firm's competitive advantage, little is known about how CEOs are deployed in H&T businesses. A significant gap in the research has been identified regarding how CEOs influence organizations in the sector. This study investigates potential synergies between H&T organizations' emphasis on CEOs and their impacts on various stakeholders. Research findings also show that CEO literature in H&T has largely focused on antecedents such as demographic, attitudinal, and organizational factors. Additionally, we suggest future research questions for CEO-related studies.