Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Gul, Muhammet(74)
- Akkurt, Nevzat(39)
- Celik, Erkan(35)
- Serdar, Osman(35)
- Güler, Ömer(33)
- Kutlu, Banu(32)
- Paksoy, Mehmet Yavuz(32)
- Yucesan, Melih(31)
- Tekin, H.O.(30)
- Yildirim, Numan(30)
- Yildirim, Nuran Cikcikoglu(30)
- ALMisned, Ghada(28)
- Mete, Suleyman(26)
- Danabas, Durali(20)
- Ince, Muharrem(20)
- Serin, Faruk(20)
- Ates, Mehmet(19)
- Can, Erkan(19)
- Onat, Onur(18)
- Benzer, Fulya(17)
- Kocabaş, Mehmet(17)
- Tanyol, Mehtap(17)
- Kizak, Volkan(16)
- Alataş, Mevlüt(15)
- Aydin, Rahmi(15)
- Kahraman, Gökhan(15)
- Kilic, G.(15)
- Polat, Alper(15)
- Susam, Selim Orhun(15)
- Xu, Qian(15)
- Aslan, Naim(14)
- Guler, Omer(14)
- Gürler, Nedim(14)
- Karatay, Gülnaz(14)
- Utku, Anıl(14)
- Yildirim, N. C.(14)
- Özkul, İskender(14)
- Demirol, Ferhat(13)
- Erguven, Gokhan Onder(13)
- Firat, Erhan(13)
Yayınlar
- Kitap BölümüYalnız künye2023A Multi-parameter Occupational Safety Risk Assessment Model for Chemicals in the University Laboratories by an MCDM Sorting Method
Gul, Muhammet; Yucesan, Melih; Karacahan, Mehmet Kayra
University laboratories are high-risk working environments where many chemicals coexist to conduct teaching and scientific research. The frequent occurrence of such chemical-related occupational accidents in recent times highlights the importance of ensuring these units’ safety in universities for researchers, students, workplaces, and institutions. In occupational safety risk assessment, very few studies have grouped risks. Many of them also ignored some important risk parameters. Overcoming these disadvantages, this study developed a multi-parameter and multi-criteria decision-making (MCDM) sorting-based methodology for the occupational safety risk assessment of chemicals in a university laboratory. First, six different risk parameters (probability, severity, exposure, detectability, worsening factor, sensitivity to non-usage of personal protective equipment) were determined. The weight value was calculated using the best–worst method (BWM). Then, a risk priority value and classification for each chemical with TOPSIS-Sort, the MCDM sorting method. Finally, some control measures are recommended to reduce the safety risk of the laboratory. The applicability of the proposed methodology has been tested with a real case study. The methodology is intended to adapt to university laboratories’ risk assessment and become a primary reference for university safety analysts.
AtıfScopus2OpenAlex1
İncele - Kitap BölümüYalnız künye2023Healthcare Logistics and Digital Transformation
Kaya, Sema Kayapınar
Due to the complex and diverse structure of the healthcare industry, the healthcare industry's logistics practices have lagged far behind sectors such as retail and manufacturing. Therefore, in today's increasingly competitive and risky environment, it is critical for hospitals to improve their logistics management performance, increase the efficiency of health services, and reduce costs. This chapter synthesizes the contributions of healthcare logistics, the impact of medical logistics on healthcare providers, types of healthcare logistics. Addition, this chapter enables us to capture the research challenges associated with the healthcare logistics process, pharma logistics and show how digitalization initiatives can address them.
AtıfScopus2OpenAlex2İncele - MakaleYalnız künye2023Scopus SJRQ2Effect of Using Eccentric Braces with Different Link Lengths on the Seismic Demand of CFST Column-Composite Beam Frames Subjected to Near-Field and Far-Field Earthquakes
Etli, Serkan; Güneyisi, Esra Mete
In recent years, in the light of technological developments, the utilization of composite members that enable the use of superior properties of concrete and steel together in earthquake-resistant building design has become widespread. In this study, 5-, 8-, 10-, 13- and 15-story composite moment-resisting framed buildings were designed using composite beams and concrete filled steel tube columns. The effect of using steel braces and the variation of the link length of the eccentric steel braces on the seismic demand of the composite buildings were investigated. For this, eight different cases with braces were considered and compared with the bare structure. The first case had concentric braces (having no link), and the other seven cases had eccentric steel braces with different link lengths classified as short, medium and long. The nonlinear dynamic response of braced and non-braced composite structures was evaluated under the effect of earthquake groups of far-field, near-field with and without pulse effects. Each earthquake group includes ten different ground motion records. SeismoStruct which is a fiber element-based software was used in modeling and analysis of the structures. Seismic behavior of the case studied structures was investigated comparatively through the demand parameters such as the maximum inter-story drift ratios, the maximum roof drift ratios and the deformation states in the structural elements. It was observed that the inclusion of the steel braces provided significant gains in dissipating seismic energy acting through composite buildings and the beam/column deformations decreased considerably, depending on the length of the link and the height of the structure. In some cases, significant damage was monitored in the link members; however, this type of deformation was limited.
AtıfScopus3WoS3OpenAlex18
İncele - MakaleYalnız künye2023Scopus SJRQ2Aluminum Recovery by Acid Leaching of Variously Enriched Pyrophyllite Ore: Effects of Pre-treatment Methods for Activation
Aydoğmuş, Ramazan; Erdemoğlu, Murat; Uysal, Turan
Effects of pre-treatment methods such as calcination for thermal activation and intensive milling for mechanical activation on the aluminum (Al) recovery by acid leaching of preliminarily enriched pyrophyllite ore via attrition scrubbing and froth flotation were investigated. XRD patterns of the calcined and the intensively milled samples were compared to determine the changes during the pre-treatment processes. Hot HCl solution was used for dissolution of aluminum to determine the Al recoveries from variously enriched and variously pre-treated pyrophyllite ore samples. Specific thermal and milling energies consumed per unit amount of ore were calculated, and the ideal activation method was suggested by comparing the activation methods in terms of energy consumption. Mechanical activation of the pyrophyllite concentrate obtained by attrition scrubbing rather than froth flotation was suggested for higher recoveries of aluminum from by acidic leaching. It was determined that operating cost (in terms of energy) of the mechanical activation is lower and aluminum recovery is higher than thermal activation. It was concluded that mechanical activation instead of thermal activation is more economical and environmentally friendly method.
AtıfScopus5WoS4OpenAlex5İncele - MakaleYalnız künye2023Scopus SJRQ2A New S-box Generator Algorithm Based on 3D Chaotic Maps and Whale Optimization Algorithm
Artuğer, Fırat
Encryption provides security in cases such as storing confidential information or transmitting it over a network. Today, block cipher algorithms are generally used for encryption. Undoubtedly, one of the most important units of block cipher algorithms to ensure confidentiality is substitution box (s-box) structures. Because s-boxes are nonlinear structures, making the algorithm resistant to differential cryptanalysis. Therefore, the higher the nonlinearity value of the s-box, the stronger it will be. In this study, a new algorithm is proposed to generate s-boxes with high nonlinearity value. In the proposed algorithm, Lorenz and Chua systems, which are 3D chaotic maps, are used for the initial population. The s-boxes produced with these chaotic maps were then increased to 110.5 using the whale optimization algorithm (WOA). WOA is one of the important optimization algorithms developed in recent years and was used for the first time in s-box production in this study. Looking at the results of the analysis, the proposed method has outstripped most of the other existing studies, thanks to effective 3D chaotic maps and WOA.
AtıfScopus44WoS38OpenAlex45İncele - MakaleYalnız künye2023Scopus SJRQ1Laboratory evaluation of oak ash waste for use in hot mix asphalt modification
Geçkil, Tacettin; Beyza İnce, Ceren; Aksağan, Zülfükar
In this study, the effect of Oak Ash (OA), a biomass waste, on the mechanical properties of hot mix asphalt (HMA) was investigated and its usability in road engineering was evaluated. For this purpose, firstly, various physical and chemical properties of B70/100 penetration class pure asphalt, OA and crushed limestone aggregate were determined. Then, the optimum asphalt content (OAC) of the mixture was determined according to the Marshall mix design method using aggregate and pure asphalt. Based on this determined content, pure and OA added (1%, 2%, 4% and 6% by weight of asphalt) modified hot mix specimens were prepared. Pure and OA added modified mixture specimens were subjected to Marshall stability, indirect tensile strength (ITS), moisture damage, indirect tensile stiffness modulus (ITSM), static-dynamic creep and calorie tests. According to the results obtained, it has been determined that the OA additive has an improving effect on all mechanical properties of the mixtures, especially on the permanent deformation resistance at high temperatures. It is considered that the use of this additive at a rate of 2% in the hot mixture can increase the resistance of the pavement against deterioration and reduce the maintenance and repair costs of the road.
AtıfScopus26WoS25OpenAlex24İncele - MakaleYalnız künye2023Scopus SJRQ1Modeling the form, distribution and paleoclimatic implications of former glaciers in the Teke Peninsula (Eastern Mediterranean, Turkey)
Keserci, Ferhat; Bayrakdar, Cihan; Çılğın, Zeynel; Evans, Ian S.
The Western Taurus Mountains on the Teke Peninsula, Southwestern Turkey, saw substantial glaciation in the late Quaternary period. Accurate reconstructions of former glacier extent in this relatively marginal area of glaciation are important for establishing the paleoclimate in the Eastern Mediterranean Basin. From west to east, the mountains of Sandıras, Karadağ, Akdağ (Kaş), and Beydağları preserve clear evidence of cirques and moraines, representing glacial valley land systems. This study used calculation tools for Glacier Reconstruction, (GlaRe) and Equilibrium Line Altitude (ELA), with glacier outlines based on the geomorphological evidence and Digital Elevation Models (DEMs), to determine the distribution and ELAs of former glaciers and to estimate paleotemperature and paleo-precipitation during the maximum ice extent. The results are analyzed at three scales: for each glacier, between glaciers and between mountain ranges. While the glaciation was at its peak, we estimate that glaciers covered a total area of 26.4 km2 (1.28 ± 0.08 km2 on Sandıras Mountain, 3.86 ± 0.23 km2 on Karadağ, 16.17 ± 0.970 km2 on Akdağ (Kaş), and 5.09 ± 0.30 km2 in Beydağları): the longest glacier was in Akdağ (Kaş) with a length of 5787 m. Average paleo-ELA (pELA) was calculated as 2077 m a.s.l in Sandıras, 2097 m a.s.l in Karadağ, 2565 m a.s.l in Akdağ (Kaş), and 2468 m a.s.l in Beydağları. Glacier modeling estimated that the maximum ice thickness in Akdağ was 240 m ± 14, and the average thickness 75 ± 4 m. Among these mountains, Karadağ had the lowest elevation to which glaciers descended (1760 ± 16 m a.s.l). Topographic analyses revealed that glaciers formed in the four mountains mostly in the North-facing localities with highest slope values of 18 to 30°. During the maximum glaciation period air temperature depression has been estimated as 8 to 9° Celsius; That required a precipitation increase of some 40 to 60 % compared to present, to produce the former glaciers mapped in the Teke Peninsula.
AtıfScopus10WoS9OpenAlex17İncele - MakaleYalnız künye2023Scopus SJRQ1A novel two-phase group decision-making model for circular supplier selection under picture fuzzy environment
Kaya, Sema Kayapinar
Circular supply chain management (CSCM), which incorporates circular thinking into supply chain management, promotes supply chain sustainability by offering a novel and compelling viewpoint. In the CSCM, supplier selection is crucial in establishing a competitive edge among businesses by decreasing environmental degradation and related supply chain expenses. This paper aims to propose a novel two-phase group decision-making approach, which combines the picture fuzzy Analytical Hierarchical Process (PF-AHP) and grey Measurement of Alternatives and Ranking According to Compromise Solution (MARCOS-G) model to select railway material suppliers within the scope of circular economy perspective. In group decision-making, a picture fuzzy number-based approach aggregates individual decision makers’(DMs) opinions and provides a lower level of computing complexity and a higher level of performance. The PF-AHP has been used to produce the weights of the criteria, and the MARCOS-G technique has been used to rank the suppliers and choose the most appropriate one. The results and verification of the novel method are carried out throughout a comprehensive sensitivity analysis. For this purpose, 50 scenarios with changes in the weight values of criteria were developed. In the validation analysis, a comparison with other grey COPRAS, TOPSIS, ARAS and WASPAS methods were performed. Due to the ranking results obtained from Spearman’s correlation analyses, the MARCOS-G is almost consistent and it can be seen that the A4 remains the top supplier in all 50 scenarios.
AtıfScopus34WoS30OpenAlex39
İncele - MakaleYayıncıda açık erişim2023Scopus SJRQ1Geochemical and radiometric data for mafic rocks from the Guleman Ophiolite (SE, Turkey): New insights on the geodynamic evolution of the southern Neo-Tethyan ocean
Sapancı, Özgür; Tokat, Gürkan; Eraslan, Nuh Kadri; Karakaya, Abdullah Onur; Gücer, Mehmet Ali; Çimen, Okay
The Guleman Ophiolite is located in the southeast of Turkey and mainly consists of harzburgites and dunites hosting economically viable chromitite bodies, and lesser amounts of cumulate and isotropic gabbro, diabase dykes, pyroxenite and locally plagiogranite. This study reports the combined whole-rock geochemical and radiogenic isotope (Sr and Nd) data for gabbro and diabase dykes, and in-situ zircon U-Pb geochronological data for plagiogranite and gabbro from the Guleman Ophiolite. Two different geochemical groups were determined based on immobile minor and trace elements, and radiogenic isotope characteristics of gabbro and diabase dykes investigated here. The first group is represented by boninites and displays highly depleted elemental patterns compared to NMORB, and spoon-shaped rare earth element profiles. Contrarily, the second group resembles back-arc basin basalts and is characterized by NMORB-like rare earth element patterns associated with negative Nb anomalies. The boninitic samples are characterized by less radiogenic 143Nd/144Nd(i) (0.51229 to 0.51267; ƐNd = −4.8 to +2.7) and more radiogenic 87Sr/86Sr(i) (0.70549 to 0.70758) isotope compositions compared to the back-arc basin basalt-like samples (143Nd/144Nd(i) = 0.51289 to 0.51296; ƐNd = +7.0 to +8.4; 87Sr/86Sr(i) = 0.70496 to 0.70629), indicating derivation from distinct and/or heterogeneous mantle source regions within a supra-subduction zone. The LA–ICP–MS zircon U-Pb analyses yielded concordant late Cretaceous ages for gabbro (82 ± 2.9 Ma) and plagiogranite (79.9 ± 0.8 Ma) samples. The overall geochemical, isotopic and geochronological data presented here suggest that the Guleman Ophiolite consists of forearc and initial back-arc spreading sections of oceanic crust, which may have been formed in an intra-oceanic subduction zone within the Berit Ocean (northern branch of the southern Neo-Tethyan ocean). Moreover, the generation of continental arc magmatism (i.e. Baskil and Esence Granitoids) was well-documented on the active margin of the Malatya-Keban Metamorphics to the north. Therefore the closure of this oceanic basin should have resulted in multiple coeval northward subduction events during the late Cretaceous.
AtıfScopus8WoS7OpenAlex9İncele - MakaleYalnız künye2023Scopus SJRQ2Chemical Characterization of Different Extracts from Artemisia annua and Their Antioxidant, Enzyme Inhibitory and Anti-Inflammatory Properties
Acquaviva, Alessandra; Nilofar; Bouyahya, Abdelhakim; Zengin, Gokhan; Di Simone, Simonetta Cristina; Recinella, Lucia; Leone, Sheila; Brunetti, Luigi; Uba, Abdullahi Ibrahim; Cakilcioğlu, Ugur
Artemisia annua L. (Asteraceae Family) is an important plant in Asia that has been used for treating different diseases, including fever due to malaria, wounds, tubercolisis, scabues, pain, convulsions, diabetes, and inflammation. In this study we aimed to evaluate the effects of different polarity extracts (hexane, dichloromethane, ethyl acetate, ethanol, ethanol/water (70 %) and water) from A. annua against the burden of inflammation and oxidative stress occurring in colon tissue exposed to LPS. In parallel, chemical composition, antiradical, and enzyme inhibition effects against α-amylase, α-glucosidase, tyrosinase, and cholinesterases were evaluated. The water extract contained the highest content of the total phenolic with 34.59 mg gallic acid equivalent (GAE)/g extract, while the hexane had the highest content of the total flavonoid (20.06 mg rutin equivalent (RE)/g extract). In antioxidant assays, the polar extracts (ethanol, ethanol/water and water) exhibited stronger radical scavenging and reducing power abilities when compared to non-polar extracts. The hexane extract showed the best AChE, tyrosinase and glucosidase inhibitory effects. All extracts revealed effective anti-inflammatory agents, as demonstrated by the blunting effects on COX-2 and TNFα gene expression. These effects seemed to be not related to the only phenolic content. However, it is worthy of interest to highlight how the higher potency against LPS-induced gene expression was shown by the water extract; thus suggesting a potential phytotherapy application in the management of clinical symptoms related to inflammatory colon diseases, although future in vivo studies are needed to confirm such in vitro and ex vivo observations.
AtıfScopus45OpenAlex43İncele - MakaleYalnız künye2023Scopus SJRQ1A holistic failure modes and effects analysis for university plastic injection laboratory under Bayesian Network
Yucesan, Melih; Gul, Muhammet; Pamučar, Dragan
University Research & Development (R&D) laboratories are facilities used for research and manufacturing activities in engineering and basic science fields. Various filling materials are used in plastic R&D laboratories to improve the mechanical properties of thermoplastics or to recycle waste materials. The use of filling materials causes changes in plastic production parameters. This study dealt with the risks arising from extrusion, injection and shredder in a plastic injection laboratory, which led to the inability to manufacture the appropriate product under a holistic methodology. The proposed holistic methodology merges the concepts of failure mode and effects analysis (FMEA), fuzzy best-worst method (FBWM), and a rule-based three-hierarchical Bayesian network (RB-THBN). First, 15 root risks have been identified under a three-stage hierarchy with the support of laboratory decision makers. Then, questionnaires were created using the FMEA concept. The importance values (degree of belief-DoB) of three different FMEA parameters (severity, occurrence and detection) by experts for each risk have been calculated with FBWM. And finally, the RB-THBN has been created, and the final risk values have been computed using the linear utility function for the network. The system has been analyzed via a Bayesian modeling software. A validity test and a control measures planning has also been executed. According to the results, the highest root risk has been determined as “E2-The prepared mixture is not homogeneous” with a crisp risk score of 0.639559. In addition, “Failure due to extrusion” has been determined as the highest risk category with a score of 0.564059. It was discussed in detail that these risks arise from homogenization and how the used mixture should be homogenized. A comparative study among traditional FMEA, FMEA extended under FBWM and the proposed approach is performed to observe the differences in final ranking of root risks and to highlight the arguments that strengthen the advantages of the proposed method over the other two.
AtıfScopus7WoS7OpenAlex8İncele - Kitap BölümüYalnız künye2023The degrowth movement in France: From the edges to the centre of the ecological debate
Karakaş, Tahir; Orofino, E; Allchorn, W
AtıfScopus1İncele - MakaleYalnız künye2023Scopus SJRQ3EFFECT OF CRYOPROTECTANT AND PRE-FREEZING ON THE SPERM MOTILITY, VIABILITY AND FERTILITY OF GOLDFISH Carassius auratus (PISCES: CYPRINIDAE) POST SHORT-TERM CRYOPRESERVATION
Nurlaili, Nurlaili; Eriani, Kartini; Salma, Itsnatani; Maulida, Siti; Rahayu, Sri Riska; Handayani, Luvi Syafrida; Kocabas, Filiz Kutluyer; Siti-Azizah, Mohd Nor; Wilkes, Martin; Muchlisin, Zainal Abidin
BACKGRUND: Goldfish Carassius auratus is a popular ornamental fish extensively cultured worldwide. Sperm cryopreservation is a common fish breeding method that ensures sperm availability around the year. Studies on cryopreservation of goldfish sperm, especially on the suitability of cryoprotectant types and pre-freezing time, are scarcely available. OBJECTIVE: To determine the most suitable type of cryoprotectant and pre-freezing for the successful cryopreservation of goldfish sperm. MATERIALS AND METHODS: A completely randomized design with two factors was utilized in this study. The first factor is the type of cryoprotectants, which included methanol, ethanol, ethylene glycol, glycerol, and DMSO. The second is pre-freezing times of 10, 20, 30, and 40 min at each of the pre-freezing temperatures of 4 0C, -10 0C, and -79 0C, meaning that the total times for the ramping down of temperature were 30, 60, 90 and 120 min, respectively. The Ringer solution and 10% egg yolk were used as extender and extracellular cryoprotectant. The sperm was stored at -179 0C for 7 days. RESULTS: The ANOVA test showed that cryoprotectants and pre-freezing significantly affected the motility, viability, and fertility of goldfish sperm after freezing in liquid nitrogen for 7 days (P<0.05). Furthermore, 10% DMSO combined with 15% egg yolk with an pre-freezing time of 20 min can maintain sperm motility, viability, and fertility higher than other treatments, by 79%, 80%, and 33%, respectively. The agarose gel electrophoresis showed no DNA fragmentation in all samples, including fresh sperm. CONCLUSION: We conclude that 10% DMSO combined with 15% egg yolk and 20 min pre-freezing is the best treatment for goldfish sperm cryopreservation.
AtıfScopus6WoS5OpenAlex5İncele - MakaleYalnız künye2023Scopus SJRQ2Graphene nanoplatelet-reinforced high entropy alloys (HEAs) through B4C incorporation: structural, physical, mechanical, and nuclear shielding properties
Gul, Ali Oktay; Kavaz, Esra; Basgoz, Oykum; Guler, Omer; ALMisned, Ghada; Bahceci, Ersin; Guler, Seval Hale; Tekin, H.O.
This study aims to explicate the diverse roles of high entropy alloys within nuclear environments. The study extensively investigates the impact of B4C on the structural, physical, mechanical, and nuclear shielding properties of synthesized high-entropy alloys (HEAs) comprising FeNiCoCrW, GNP, and B4C. The aim is to explore the monotonic effects of B4C on the behavioural changes of the HEAs. The present study initially investigates the internal morphology and structural characteristics of the produced composites through the utilization of X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. The determination of coefficient of friction values is obtained via wear testing, wherein the values are measured as a function of the sliding distance. The shielding properties of nuclear radiation are determined through the experimental setups for gamma-ray and neutron radiation. The sample encoded as G2, which incorporates both B4C and GNPs as reinforcing agents, exhibits the most noteworthy mechanical properties among the samples that were examined. The findings of our study indicate that augmenting the concentration of B4C has a significant impact on the efficacy of nuclear radiation shielding. The present study infers that the B4C produced within the framework of GNPs plays a significant role in enhancing the overall characteristics of HEAs. This is particularly noteworthy in the context of nuclear applications, where HEAs are being examined as a prospective constituent of forthcoming nuclear reactors. Moreover, B4C serves as a versatile instrument in scenarios, where there is a need to enhance mechanical and nuclear shielding properties across a spectrum of radiation energies.
AtıfScopus15OpenAlex16İncele - MakaleYalnız künye2023Scopus SJRQ1Evaluation of container port sustainability using WASPAS technique using on type-2 neutrosophic fuzzy numbers
Kaya, Sema Kayapinar; Kundu, Pradip; Görçün, Ömer Faruk
According to the common opinion in the literature, the sustainability of container ports is a tremendously complex topic owing to the maritime sector's excessively dynamic form and many highly complex, predictable and unpredictable uncertainties in this industry. The current paper proposes two powerful, practical, inspiring approaches to fill these gaps. It proposes a novel type-2 neutrosophic fuzzy numbers (T2NFNs) based Delphi method to determine the criteria logically and optimal and extends the WASPAS technique based on the T2NFNs for evaluating the alternatives. The current paper presents practical managerial implications that many stakeholders can consider, such as port authorities, ship owners, logistics service providers, governments, and local authorities, when making strategic and managerial decisions. In addition, the results of a comprehensive sensitivity analysis performed to test the robustness and applicability of the model approve the validity of the proposed T2NFN-based integrated approach.
AtıfScopus20WoS16OpenAlex24İncele - Kitap BölümüYalnız künye2023Organizational change models in practice: The case of michelin group
Uyan, Umut
In a competitive business environment, it is vital that firms consider implementing techniques to cope with constant change to remain competitive and survive. Most change initiatives, however, suffer from several difficulties and are often hampered by resistance, primarily caused by fear of adopting new practices or concern about competence. As a result, such initiatives could result in unintended consequences. In fact, they might result in irreversible situations, impairing the dynamics of an organization. Michelin Shanghai underwent an organizational change initiative to enhance its competitiveness. The initiative resulted in significant improvements in the company's productivity and profitability as well as increased employee satisfaction. The main objective of the study is to understand the organizationalchange dynamics of Michelin Shanghai Co. The chapter also attempts to evaluate challenges encountered during the process and critically analyze the leadership approaches that were applied by Mr. Ballarin (plant manager of Michelin Co.) based on related theories.
AtıfScopus1OpenAlex1İncele - MakaleYalnız künye2023Scopus SJRQ2Investigation of Leaching Kinetics of Molybdenum from MoO3 Concentrate in Ammonia–Ammonium Nitrate Solutions
Karacahan, Mehmet Kayra
MoO3 is a widely accessible foundation material and the primary compound used to produce numerous molybdenum products. The ore was first roasted, and the leaching behavior of concentrated molybdenite mineral was assessed. The optimal conditions for the leaching process were identified in the second step, and in a subsequent stage, the process' kinetics were assessed. Ammonia and ammonium nitrate concentration were used as independent variables in the trials, and the central composite design approach was used to analyze the results. At the conclusion of the tests, the optimum concentrations of ammonia and ammonium nitrate were found to be 2.42 mol/L and 1.86 mol/L, respectively. On the rate at which molybdenum leached from MoO3, the influences of temperature, stirring speed, solid-to-liquid ratio, and particle size were investigated. It was found that the leaching rate increased when temperature and stirring speed increased, along with decreasing the solid-to-liquid ratio and particle size. Leaching efficiency of molybdenum (93%) such as temperature 20 °C, 1.859 mol/L ammonium nitrate concentration, 2.419 mol/L ammonia concentration, solid/liquid ratio 6/100 g/mL, stirring speed 400 rpm, and average particle size 0.115 mm optimum conditions have been achieved. The kinetic study proposed a mathematical model for the leaching process, which revealed that the leaching kinetics matched the Avrami model. This process' activation energy was determined to be 22.66 kJ/mol. Calcium molybdate is used in various fields, such as construction, transportation, anti-corrosion pigments, and flame retardants. Graphical Abstract: [Figure not available: see fulltext.]
AtıfScopus8WoS7OpenAlex9İncele - MakaleYalnız künye2023Scopus SJRQ1Acrylamide formation in apple juice concentrates during storage
Aktağ, Işıl Gürsul; Gökmen, Vural
This study investigated the acrylamide formation in model systems, laboratory-scale produced apple juice concentrates obtained from different stages of process, and commercial apple juice concentrates at different Brix levels during the storage. Changes in the concentrations of reducing sugars, asparagine, 5-hydroxymethylfurfural, 3-deoxyglucosone, and acrylamide were monitored. In addition, Schiff bases of 3-deoxyglucosone and 5-hydroxymethylfurfural with asparagine were confirmed using high-resolution mass spectrometry in order to understand the contribution of intermediates to acrylamide formation. The results revealed that acrylamide formed in both acidic-aqueous model systems and laboratory-scale apple juice concentrates during production. The concentrations of 3-deoxyglucosone, 5-hydroxymethylfurfural, and acrylamide increased significantly (p < 0.05) with the increase in Brix levels whereas asparagine levels decreased in commercial apple juice concentrates during storage. The concentration of acrylamide reached at the maximum level of 0.30 ± 0.02 µmol/kg dry matter in 70°Bx of the concentrates. The findings showed that long-term storage of apple juice concentrates at high Brix levels contributes the acrylamide formation even in unsuitable systems such as acidic and high moisture medium. The confirmation of Schiff base of 3-deoxyglucosone and 5-hydroxymethylfurfural with asparagine demonstrated that the acrylamide formation was attributed to the accumulation of intermediates leading to the conversion of asparagine to acrylamide.
AtıfScopus9WoS8OpenAlex9İncele - MakaleYalnız künye2023Scopus SJRQ1Analysis of the mechanical characteristics and plasticity-hazardous zones development of natural gas pipeline under overload
Zheng, Qiang; Shu, Zekai; Yang, Gang; Zhang, Hui; AKKURT, Nevzat; Guan, Ben; Chen, Weiwang; Xu, Qian; Zang, Yong; Ding, Yulong
The problem of natural gas pipeline overload failure is of great significance, and the development law of critical mechanical properties of pipelines is of great importance to the safety design of natural gas pipelines. This study establishes a three-dimensional finite element computational model of the pipeline that integrates the changes in axial and circumferential mechanical characteristics, and uses the yield strength, safety factor and ellipticity indexes as criteria to dimensionless the axial depth and circumferential angle of the plastic zone to explore the characteristics of the plastic damage stage of the pipeline. By solving the plastic hazardous zones based on the safety factor, the applicability of the dimensionless parameters is extended to investigate the development laws of the hazardous zones and the correlation mechanism between failure criteria and hazardous zones. The results show that as the ground load increases, the pipeline deformation gradually develops into the plastic stage (P = 16 MPa) and then goes through three deformation stages. With the increase of safety factor, the change trend of the proportion of stage I in the whole loading process decreases to 4 %, the change trend of the proportion of stage III increases significantly to 52 %, while the proportion of stage II shows a change trend of decreasing and then increasing, the proportion of this stage ranges from 30 % to 38 %. Based on the law of variation of axial ellipticity of pipeline section, a high-risk section of pipeline was identified in the range of 0–2 m from the point of maximum local compression strain. The results of the study can serve as a basis for accurate evaluation of the safety status of natural gas pipelines under overload.
AtıfScopus3WoS3OpenAlex3İncele - MakaleYalnız künye2023Scopus SJRQ1A data-driven evaluating method on the defrosting effect of the air source heat pump system in Beijing
Guo, Yanhua; Shao, Shuangquan; Geng, Xudong; Li, Hao; Wang, Zhichao; Akkurt, Nevzat
The current demand-based defrosting initiation strategies of air source heat pumps (ASHPs) faces difficulty in achieving a balance between cost and robustness. Therefore, an efficient and innovative demand-based defrosting initiation strategy is proposed in this paper, based on the learned the degradation of heating capacity (DHC) method using data-driven model. Firstly, the DHC method is developed using the initially installed sensors without additional sensors to identify the frosty state. Subsequently, the fully connected neural network (FNN) model is established for predicting frosty state using field measured data from the ASHP system. Finally, the effectiveness of the defrosting initiation strategy is further validated through practical testing. The results demonstrate that the DHC method provides a reliable database for training the FNN model, resulting in an impressive accuracy of 91.43% for predicting the frosty state in the testing set. By adopting the innovative demand-based defrosting initiation strategies, the defrosting frequency, heating loss, and power consumption are respectively decreased by 66.3%, 2.1%, and 6.0% with the SCOP enhanced by 8.6% during a heating season. The promising results highlight that the proposed strategy effectively reduces costs while ensuring the efficiency of demand-based control.
AtıfScopus23WoS22OpenAlex27İncele