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51.
Seniha Micoogullari Kurt Mehmet Emin Kaval Burcu Serefoglu Gzde Kandemir Demirci Mehmet Kemal alkan 《Microscopy research and technique》2020,83(7):790-794
The aim of this study was to evaluate the cyclic fatigue resistance of Dia‐X, WaveOne Gold and One Curve files in a water bath at intracanal temperature (35°C). Thirty‐nine instruments Dia‐X, WaveOne Gold, and One Curve systems (n = 13) were tested in an artificial canal with a curvature angle of 60° and a radius of 3 mm. A water bath setup at a temperature of 35°C was used to simulate the intracanal temperature and time to fracture (TTF) as seconds was recorded. The mean data were analyzed statistically using one‐way ANOVA, and post hoc Tukey test (p = .05). The fractured surface of the instruments was examined with scanning electron microscopy (SEM) and chemical composition of the instruments were investigated with energy dispersive X‐ray spectroscopy (EDS). Statistically significant differences were detected in TTF values of all the systems as follows: One Curve > WaveOne Gold > Dia‐X (p < .05). One Curve instruments demonstrated the highest TTF values in all the tested instruments. The EDS microanalysis revealed similar NiTi composition of on the surface of One Curve, WaveOne Gold, and Dia‐X instruments. The novel manufacturing process, including C‐wire heat treatment and the variable cross‐section of the One Curve files, could be the main factors affecting the fatigue life of the instruments. 相似文献
52.
Hatice Gözde Akkın Gürbüz Türkay Demir Burcu Gökalp Özcan Muhammed Tayyib Kadak Burç Çağrı Poyraz 《Behaviour & Information Technology》2017,36(5):517-523
Social network sites (SNSs) are relatively new phenomena, and the relationship between SNSs and psychopathology remains unclear. The purpose of this study was to evaluate the type of SNSs depressed adolescents use and the incidence of depressive disclosure on SNSs among them. The study was designed to be cross-sectional. The sample consisted of 53 adolescents diagnosed with depressive disorder, as confirmed by K-SADS-PL, and 55 non-depressed adolescents. The Children’s Depression Inventory, Social Anxiety Scale and Social Network Use Questionnaire were administered. The primary finding was that the amount of time spent on the Internet and on SNSs was significantly higher among depressed adolescents than non-depressed adolescents. Additionally, depressed adolescents reported significantly higher disclosure of anhedonia, worthlessness, guilt, loss of concentration, irritability and thoughts of suicide on SNSs. The intensity of the depression sharing was significantly higher in the depressed group. Depressed young people use social networks to express their symptoms. Adolescents’ disclosure on social networks may be able to guide relatives, friends and mental health professionals. 相似文献
53.
Although artificial neural networks (ANN) are more known in the field of image recognition and forecasting, cost estimation has become another emerging area in recent years. In this study, the establishment of an intelligent system was attempted for forecasting the total cost of sheet metal stamping dies. In this context, where the cost of stamping dies is estimated with a conventional approach which has been applied in the company up to now, the ANN and multiple regression analysis and the performance of the three cost-estimation models are examined. The examinations are based on the data of previous costs and use a number of critical criteria which are decided by experienced tool makers and engineers from every level of the organization of the seven companies which produce stamping dies. The comparative study reveals that the ANN system outperforms the traditional linear regression analysis model and conventional approach used for cost estimation. Thus, it is possible for firms which produce stamping dies to obtain a fairly accurate prediction with an ANN model and determined criteria. 相似文献
54.
Burcu Dedeoğlu İlke Uğur İsa Değirmenci Viktorya Aviyente Bilinç Barçın Gökhan Çaylı Havva Yagci Acar 《Polymer》2013
A capto-dative monomer, 2-acetamidoacrylic acid (AAA), was homopolymerized through RAFT polymerization method using 2-(2-cyanopropanyl dithiobenzoate) (CPDB) as a chain transfer agent and AIBN free radical initiator in DMF at 70 °C. DFT calculations were performed in the selection of the CTA for this unique monomer as well as to elucidate the influence of cd-stabilized growing radical on the kinetic parameters in comparison to methacrylic acid (MAA) and N-(prop-1-en-2-yl)acetamide (NPAA), which represent the captive and dative groups of AAA, respectively. Keq for these three monomers is in the order of AAA < MAA < NPAA. While kβ > k−add for NPAA and MAA, for AAA k−add is about four orders of magnitude larger than kβ. This is the major disadvantage in the RAFT process of AAA using CPDB. Yet, poly(AAA) could be achieved with PDI as low as 1.49. Molecular weight of the polymer can be tuned by the monomer/AIBN ratio. First block copolymers of AAA with MAA and MMA using poly(AAA) as a macro-CTA were also synthesized, indicating the presence of active chain ends. 相似文献
55.
Emre Baştürk Burcu OktayMemet Vezir Kahraman Nilhan Kayaman Apohan 《Progress in Organic Coatings》2013
In this study, bis-(triethoxysilylpropyl) phenyl phosphamide (BESPPA) was synthesized by the reaction between dichlorophenyl phosphine oxide and 3-aminopropyltriethoxysilane. The chemical structure of the BESPPA was characterized with Fourier transform infrared and NMR techniques. Flame retardant, BESPPA and sol–gel precursor containing hybrid materials were prepared by thiol-ene polymerization with the aim to improve their final thermal and flame retardant properties. The thermal stabilities of the phosphorous/sol–gel containing UV-cured hybrid materials were investigated by thermogravimetric analysis. The results showed that the addition of sol-gel precursor and BESPPA into the organic network also improves the thermal-oxidative stability of the hybrid materials. The flame-retardant properties of the UV-cured hybrid materials were also studied. Furthermore, the phosphorus–silicon synergistic effect on LOI enhancement and increasing flame retardancy of the UV-cured hybrid materials were demonstrated. An LOI enhancement from 20.7 to 26.5 is observed for organic resins containing both phosphorus and silicon. The surface morphology was also characterized by scanning electron microscopy (SEM). SEM studies indicated that inorganic particles were dispersed homogenously throughout the organic matrix. 相似文献
56.
Ferruh Özbudak Burcu Gülmez Temur 《Applicable Algebra in Engineering, Communication and Computing》2007,18(5):433-443
We study the general fibre product of any two Kummer covers of the projective line over finite fields. Under some assumptions,
we obtain an involved condition for the existence of rational points in the fibre product over a rational point of the projective
line so that we determine the exact number of the rational points. Using this, we construct explicit examples of such fibre
products with many rational points. In particular we obtain a record and a new entry for the table (http://www.science.uva.nl/~geer/tables-mathcomp15.ps).
相似文献
57.
Indoor localization is needed for guiding people who are not familiar with a facility. This need is more critical when guidance is needed to locate people or objects that need immediate attention. For example, an inexperienced facility worker might need to locate a building component (e.g., leaking pipe) for repair to prevent any damage to a facility or its residents. In such situations, an approach that can help the user to reach his/her destination point (i.e., a component of interest or a specific location in a facility) based on his/her current location is desired. To provide such guidance, the location of a person needs to be determined at a given point in time. This process is known as localization. The objective of this research study is to determine the technological viability of using radio frequency identification (RFID) to support localization. To assess the capability of RFID for localization, the writers conducted multiple field tests under real operating conditions within a facility at Carnegie Mellon University. Hypothesis tests and K-nearest neighborhood algorithm were used to determine the technological feasibility of RFID to support localization. The results showed that it is possible to identify the location of a user using this approach; however, some improvements in accuracy are needed. 相似文献
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Objective: The aim of this in vitro study was to evaluate the bond strength of a new calcium silicate cement, Neo MTA Plus (Avalon Biomed Inc. Bradenton, FL, U.S.A) by comparing ProRoot MTA and Biodentine.Material and Methods: Sixty dentin slices were instrumented to achieve a diameter of 1.3 mm. Group 1: white ProRoot MTA, group 2: Biodentine, group 3: Neo MTA Plus – G (powder mixed with gel), group 4: Neo MTA Plus – W (powder mixed with distilled water) were loaded into cavities. The push-out bond strength values were measured. Data were analyzed using Welch ANOVA with Bonferroni correction p = 0.05. Failure modes (adhesive, cohesive, and mixture) were analyzed.Results: The highest bond strength value was recorded in Neo MTA Plus mixed with gel (5.23 ± 1.78 MPa), whereas white ProRoot MTA (2.57 ± 0.66 MPa) had the lowest. Bond strength values of Neo MTA Plus mixed either with gel or with distilled water were statistically different from both white ProRoot MTA and Biodentine (2.61 ± 0.70 MPa) (p < 0.05). Adhesive failure was predominantly observed in all groups.Conclusion: Neo MTA Plus could be considered as alternatives to the ProRoot MTA and Biodentine due to its better performance in bonding to root dentin. 相似文献