WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
Browse
19 results
Search Results
Now showing 1 - 10 of 19
Article Citation - WoS: 4Citation - Scopus: 3Enhancement of Post-Harvest Quality of Fresh Mandarins With Alginate-Based Edible Coating Containing Natamycin and Vanillin(Springer, 2024) Takma, Dilara Konuk; Korel, FigenEnvironmentally friendly technologies with regard to reducing the usage of commercial synthetic waxes are required for maintaining the quality of mandarin fruits during the post-harvest period. In this study, novel biocoatings that serve as a natural alternative to synthetic waxes were developed for obtaining sustained shelf life of freshly harvested mandarins. The effect of natamycin and vanillin as natural antimicrobial compounds on the post-harvest quality of mandarins were investigated by means of alginate-based edible coating. Alginate coating (1% w/v) formulations including 0.5% vanillin, 1.0% vanillin, 0.025% natamycin, 0.05% natamycin and without vanillin or natamycin were applied and compared with uncoated fruit as control. Weight loss, color change, fruit firmness, yeast and mold counts were examined over 21 days at 25 degrees C. Quality changes in mandarins such as losses of weight, color and softening changes were significantly delayed with alginate coatings. Brightness on the surfaces of fruits was improved by alginate coating layers. Fruit firmness decreased with storage time in control samples, while the firmness in coated samples remained relatively constant or increased. Moreover, yeast and mold counts considerably decreased (1.52 log cfu/g) for fruits coated with alginate coating incorporating 1% vanillin. Extension of the post-harvest storage of mandarin fruits could be performed by using alginate coating incorporating vanillin as an alternative to synthetic waxes.Book Part Citation - WoS: 1Citation - Scopus: 1A Historical Review of Polyhedral Linkages(Springer, 2024) Kiper, GökhanPolyhedral linkages are linkages that resemble polyhedral shapes at different configurations. This paper summarizes the necessary geometrical fundamentals of polyhedral geometry and presents a historical and critical review of the polyhedral linkage designs available in the literature. Basic definitions of polyhedral geometry and operations are needed to comprehend and design polyhedral linkages. First, early works on polyhedral linkages are presented, where flexible polyhedra with rigid faces and flexible edges are issued. The final part is reserved to conformal polyhedral linkages, which go through shape transformations while plane, dihedral and solid angles are preserved. Conformal polyhedral linkages are examined in four categories: 1) Jitterbug-like linkages with screwing polygonal links connected to each other with dihedral angle preserving links, 2) polyhedral linkages with planar kinematic chains in radial motion planes, 3) polyhedral linkages with planar kinematic chains on faces, that are connected to each other with dihedral angle preserving links, and 4) other conformal polyhedral linkages. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.Conference Object Method of Hydrodynamic Images and Quantum Calculus in Fock-Bargmann Representation of Quantum States(Springer, 2024) Pashaev,O.K.We propose a new approach to quantum states in Fock space in terms of classical hydrodynamics. By conformal mapping of complex analytic function, representing the wave function of quantum states in Fock-Bargmann representation, we define the complex potential, describing these quantum states by incompressible and irrotational classical hydrodynamic flow. In our approach, zeros of the wave function appear as a set of point vortices (sources) in plane with the same strength, allowing interpretation of them as images in a bounded domain. For the cat states we find fluid representation as descriptive of a point source in the oblique strip domain, with infinite number of periodically distributed images. For the annular domain, the infinite set of images is described by Jackson q-exponential functions. We show that these functions represent the wave functions of quantum coherent states of the q-deformed quantum oscillator in q-Fock-Bargmann representation and describe the infinite set of point vortices, distributed in geometric progression. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.Article Citation - WoS: 3Citation - Scopus: 4Frequency-Specific Sensitivity of 3t3-L1 Preadipocytes To Low-Intensity Vibratory Stimulus During Adipogenesis(Springer, 2022) Baskan, Öznur; Sarıgil, Öykü; Meşe Özçivici, Gülistan; Özçivici, EnginAdipocyte accumulation in the bone marrow is a severe complication leading to bone defects and reduced regenerative capacity. Application of external mechanical signals to bone marrow cellular niche is a non-invasive and non-pharmaceutical methodology to improve osteogenesis and suppress adipogenesis. However, in the literature, the specific parameters related to the nature of low-intensity vibratory (LIV) signals appear to be arbitrarily selected for amplitude, bouts, and applied frequency. In this study, we performed a LIV frequency sweep ranging from 30 to 120 Hz with increments of 15 Hz applied onto preadipocytes during adipogenesis for 10 d. We addressed the effect of LIV with different frequencies on single-cell density, adipogenic gene expression, lipid morphology, and triglycerides content. Results showed that LIV signals with 75-Hz frequency had the most significant suppressive effect during adipogenesis. Our results support the premise that mechanical-based interventions for suppressing adipogenesis may benefit from optimizing input parameters.Conference Object Citation - Scopus: 3Seismic Performance of Cfrp Jacketed Sub-Standard Rc Columns Under High Axial Stress and Shear Demand(Springer, 2022) Demir, Merve Nur; Demir, Uğur; Demir, Cem; İlki, AlperIn the last decades, lessons learnt from the major earthquakes, that occurred in many countries, brought revisions in prevailing seismic design codes. As a consequence of this phenomenon, the current building stock in Turkey is mainly comprised of reinforced concrete (RC) buildings which were designed according to different seismic design codes. The presented paper is a component of a comprehensive investigation which containing three variables i) high axial load ratio defined as axial load divided by the axial capacity, ii) high shear demand defined as the ratio of shear demand at flexural yielding to shear resistance and iii) low transverse reinforcement ratio owing to large spacing among steel reinforcements. Thus, a total of four full-scale square RC columns comprised of i) one column designed to comply with the former Turkish Seismic Design Code (TSDC, 1975) and ii) three columns which are not compliant to any design codes (referred as sub-standard), were tested under high axial load ratio, 0.4 for code-conforming and 0.75 for sub-standard columns, combined with reversed cyclic lateral loading. The columns were also designed to have high shear demand in the order of 0.62 and 0.80 for bare sub-standard according to ACI 318 (2019) and TBEC (2018) design codes as sometimes observed in existing sub-standard structures. In addition to that, the ratio of shear demand for the code-conforming column is calculated 0.43 and 0.50 as per design codes, respectively. Besides, the ratio of transverse reinforcement area to the minimum required transverse reinforcement area was 0.19 and 0.77 for sub-standard columns according to ACI 318 (2019) and TBEC (2018), respectively. For the code-conforming column, the aforementioned ratio was 0.57 and 1.32 for both design codes, in the same manner. One of the sub-standard columns was kept as a reference column while the other two of them have been externally jacketed with one layer or two layers of carbon fiber-reinforced polymer (CFRP) sheets. Test results pointed out that the confinement provided by CFRP jacketing has remarkably improved the performance of seismically-deficient RC columns subjected to high axial compression under high shear demand in terms of lateral load capacity and ductility. The experimental results were also supplemented with theoretical work to evaluate the effects of CFRP jacketing on the seismic behavior of sub-standard RC columns.Conference Object Citation - WoS: 1Citation - Scopus: 2Seismic Performance of Substandard Rc Columns Retrofitted With Sprayed Gfrm(Springer, 2022) Kian, Nima; Demir, Uğur; Demir, Cem; Maraşlı, Muhammed; İlki, AlperThere is a myriad amount of substandard reinforced concrete (RC) buildings in developing countries that do not comply with the requirements and instructions of the current building design codes. In particular, columns in these substandard buildings demonstrate unsatisfactory and undesired behavior against lateral loads, mainly due to low concrete compressive strength and poor reinforcement detailing. The problem is exacerbated when the axial load ratio (ratio of applied axial load to the axial load capacity) and/or the shear ratio (ratio of shear force corresponding to moment capacity (Ve) to the shear capacity (Vr)) is/are high, leading to brittle failure modes. In this study, three full-scale substandard RC columns subjected to high axial load ratio of 0.75 were tested under constant axial load combined with reversed cyclic lateral displacements. Shear ratio (Ve/Vr) of the substandard columns were 0.75 and 0.82 according to ACI 318-19 (ACI 318 (2019) Building Code Requirements for Structural Concrete. American Concrete Institute, Farmington Hills, MI, USA) and (Turkish Building Earthquake Code (Turkish Building Earthquake Code (TBEC) (2018) Disaster & Emergency Management Authority, Ankara, Turkey), respectively. According to the TBEC (Turkish Building Earthquake Code (TBEC) (2018) Disaster & Emergency Management Authority, Ankara, Turkey), columns had a high Ve/(fctmbd) ratio of 1.12, where, fctm, b, and d are the direct tensile strength of concrete, width of the cross-section, and effective depth of the section. The ratio of transverse reinforcement to minimum required transverse reinforcement according to the ACI 318-19 (ACI 318 (2019) Building Code Requirements for Structural Concrete. American Concrete Institute, Farmington Hills, MI, USA) and TBEC (Turkish Building Earthquake Code (TBEC) (2018) Disaster & Emergency Management Authority, Ankara, Turkey) was 0.19 and 0.77, respectively. Two of the columns were retrofitted with an innovative, cost-effective, and easily-applicable strengthening method, through external jacketing with sprayed glass fiber reinforced mortar (GFRM) of different characteristics. The remaining column was tested as the reference specimen to evaluate the efficiency of the strengthening method. The test results demonstrated the extremely poor performance of the reference substandard column as well as the remarkable lateral load capacity and ductility improvement provided by the adopted novel strengthening approach.Conference Object Pre-Study of the Dissolution Behavior of Silicon Kerf Residue in Steel(Springer, 2022) Lazou, Adamantia; Nilssen, David; Gökelma, Mertol; Wallin, Maria; Tranell, GabriellaSilicon kerf residue is generated during the wafering process of pure silicon in the photovoltaic value chain. The generated by-product has a high volume, and the particle size is typically below 1 μm. Although the fine particles are partly oxidized, the material may be beneficial in different metallurgical applications such as grain refining and alloy composition adjustments. This work studies the dissolution behavior of silicon kerf in low alloy steel melts with the aim to upcycle the kerf material in the steel industry for different purposes. In this study, a steel alloy and the kerf residue were melted (at 1580 °C) in an alumina crucible placed in an induction furnace. The amount of added kerf residue was varied. The behavior of the particles in the solidified alloy was characterized by using an optical microscope, electron probe microscope (EPMA), and wavelength-dispersive X-ray spectroscopy (WDS) in order to study the dissolution behavior of the Si-kerf residue in the steel.Conference Object A sustainable association case study: IFToMM member organization Turkey(Springer, 2022) Kiper, Gökhan; Söylemez, EresAs a member of IFToMM founded in 2011, Turkish Machine Theory Association’s (MakTeD) structure has put special emphasis on sustainability of the association and initiated several activities for improving the quality of education and research in mechanism and machine science area, hence supporting the SDG4 Quality Education of the UN. This paper presents the activities and methodologies of MakTeD. The paper starts with a brief history of mechanism and machine science in Turkey. In 10 years MakTeD organized 4 symposiums, 1 conference, 4 summer/winter schools, 8 workshops and hosted an IFToMM Executive Council meeting. Each chapter of the biyearly held National Symposium on Theory of Machines is held by a different university and especially newly established and the universities in relatively smaller cities are prioritized in order to promote those universities and to contribute to development of these universities. Especially the summer/winter schools and workshops have a widespread impact on mechanism and machine science education and research at the universities and institutions. MakTeD also contributes to the community with published books and support programs for young researchers.Conference Object Digital Twin of a Servo Driver of a Servo Motor as a First Step Towards a Digital Twin of a Robot Mechanism(Springer, 2022) Küçükoğlu, Sefa Furkan; Carbone, Giuseppe; Dede, Mehmet İsmet CanDigital Twin (DT) offers us to acquire actual system’s critical information and hence, it may be possible to develop and produce more suitable systems in terms of low energy consumption and effectiveness. In this way, responsible consumption and production systems can be designed and the system’s parameters can be tuned via DT. In this study, the model of a servomotor system that is used for industrial purposes is experimentally obtained. This study consists of two steps. In the first step, within the embedded control of the system, position and velocity control loops are deactivated. Then through the servo driver, currents with sinusoidal waveforms at various frequencies are applied to the servomotor. The resultant angular velocity of the motor is monitored and recorded. The amplitude of the current is kept constant during this study. The frequency of the current, however, is increased logarithmically. By using these data, a first-order transfer function (TF) is identified for the motor model. In the second step, all control loops are activated. Consequently, the total servomotor system could be represented in a digital environment. Furthermore, the static friction issue is overcome by using a Coulomb friction model with stiction effect. Finally, several experiments are conducted and then results are compared with the digital model of the servomotor system. The results clearly show that digital model can fairly represent the physical system.Conference Object Citation - WoS: 2Citation - Scopus: 1The Influence of the Casting Speed in Horizontal Continuous Casting of Aluminium Alloy En Aw 6082(Springer, 2021) Obalı, Akın; Dilek, Kerem Ahmet; Akdi, Seracettin; Ürk, Deniz Kavrar; Gökelma, MertolVertical direct chill (VDC) casting is commonly used to produce slabs and billets from wrought aluminium alloys. The fact that the VDC is not a continuous process and moulds must be prepared for the next batch decreases the productivity of the process. Alternatively, horizontal direct chill (HDC) casting simplifies the process and allows a continuous production. The casting speed in the HDC casting is easier to control and can be optimized for different alloys by changing the speed. This study focuses on investigating the effects of casting speed on the macrostructure of 6082 aluminium billets with 60 mm diameter. A demo-scale casting unit was used and the casting speed was changed from 310 to 385 mm/min. Changes in surface condition, macrocracks, microporosity, and diameter of the billets were investigated. Surface quality of the billets became better with the increasing casting speed, while diameter of the billet expands. Furthermore, centreline cracks appear at the casting speed of 355 mm/min. © 2021, The Minerals, Metals & Materials Society.