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81.
A study is reported in which a series of dental cements of varying types (zinc phosphate, zinc polycarboxylate, glass-ionomer and resin-modified glass-ionomer) was exposed to aqueous solutions of differing pH for time intervals of a week, after which the pH of the storage solutions was determined. The results showed that all of the acid-base cements altered the pH of their storage solution, regardless of whether that initial solution was weakly acidic, weakly alkaline or close to neutral. All cements were found to act as buffers, because they not only increased the pH of the weakly acidic lactic acid solution, but they also decreased the pH of the weakly alkaline artificial saliva. In deionized water, the zinc polycarboxylate generally increased pH, while all other cements reduced it. In all cases, these results were shown to be repeatable on exposure to fresh-aqueous solutions of the appropriate pH for a further week, such experiments being carried out for up to six weeks. In terms of mass change, in most solutions, there was a modest increase during the first week, after which the mass remained steady. In lactic acid, zinc phosphate and zinc polycarboxylate cements showed a gradual reduction in mass throughout the six weeks, whereas the glass-ionomers showed an initial increase, followed by a much slower decrease in mass. These results confirm that glass-ionomers are the most resistant of the cements towards acid erosion. 相似文献
82.
Kaveh Mohammad Amiri Chayjan Reza Taghinezhad Ebrahim Abbaspour Gilandeh Yousef Younesi Abdollah Rasooli Sharabiani Vali 《Engineering with Computers》2019,35(3):1045-1058
Engineering with Computers - In this paper, multi-stage continuous belt (MSCB) dryer was used for carrot slices drying. Experiments were performed at three air speeds (1, 1.5, and 2 m/s)... 相似文献
83.
Ghobadi Nader Hafezi Fatemeh Naderi Sirvan Amiri Fatemeh Luna Carlos Arman Ali Shakoury Reza Ţălu Ştefan Rezaee Sahar Habibi Maryam Mardani Mohsen 《Semiconductors》2019,53(13):1751-1758
Semiconductors - The purpose of this research is to explore the properties of CoSe nanostructured thin films on glass substrates prepared by a chemical solution deposition method. Special attention... 相似文献
84.
Sivakumar P. Nagaraju Regonda Samanta Debabrata Sivaram M. Hindia Mhd. Nour Amiri Iraj Sadegh 《Wireless Networks》2020,26(4):2317-2328
Wireless Networks - Nowadays, the smart grid has demonstrated a great ability to make life easier and more comfortable given recent advances. This paper studies the above issue from the perspective... 相似文献
85.
Amiri Aryan Dardel Morteza Daniali Hamidreza Mohammadi 《Multibody System Dynamics》2019,47(4):363-395
Multibody System Dynamics - In the current study, the dynamic behavior of two planar mechanisms with revolute joints, in the presence of clearances is investigated. Subsequently, a control scheme... 相似文献
86.
Salehifar Hananeh Bayat Peyman Majd Mojtaba Amiri 《Multimedia Tools and Applications》2019,78(12):16861-16885
Multimedia Tools and Applications - Authentication systems in which eye is used for entering the password are categorized into two gaze-based and gesture-based groups. In the accurate... 相似文献
87.
Hatef Fotuhi Amirhossein Amiri Mohammad Reza Maleki 《Quality and Reliability Engineering International》2018,34(4):572-588
Nowadays, due to the increasing role of social networks in our daily life, monitoring and forecasting social trends have attracted the attention of many researchers. To the best of the authors' knowledge, the literature includes few studies of monitoring social networks. Existing researches have focused on analyzing only the existence of communications between people and have neglected to monitor the number of such communications. In this paper, first counts of communications between people are modeled using Poisson regression profiles. Then, 3 Phase I monitoring methods, extended T2, F, and a standardized likelihood ratio test method is suggested to detect step changes, drift, and outliers in the parameters of Poisson regression profiles. The proposed methods are evaluated via simulation studies in terms of signal probability criterion. The results show that in most out‐of‐control situations the standardized likelihood ratio test method outperforms the T2 and F methods. Then, a numerical example and a case study based on Enron email data are presented to illustrate the application of the extended methods. 相似文献
88.
Alireza Nikpourian Mohammad Reza Ghazavi Saber Azizi 《International Journal of Mechanics and Materials in Design》2018,14(1):1-19
Size dependent static and dynamic behavior of a fully clamped micro beam under electrostatic and piezoelectric actuations is investigated. The microbeam is modeled under the assumptions of Euler–Bernoulli beam theory. Viscous damping and nonlinearities due to electrostatic actuation and mid-plane stretching are considered. Residual stress and fringing field effect are taken into account as well. Governing equation of motion is derived using Hamilton’s principle along with the strain gradient theory (SGT), which is a non-classical continuum theory capable of taking size effect of elastic materials into account. Reduced order model of the partial differential equations of the system is obtained using Galerkin method. Static deflection, pull-in voltage and the primary resonance of the microbeam are examined and the effect of piezoelectric voltage and its polarization on the size dependent static and dynamic response is studied. It is found that the piezoelectric voltage can effectively change the flexural rigidity of the system which in turn affects the pull-in instability regime. The effect of material length scale parameter is examined by comparing the results of the SGT with the modified couple stress (MCST) and classical theory (CT), both of which are special cases of the former. Comparison demonstrates that the CT underestimates the stiffness and consequently the pull-in voltage and overestimates the amplitude of periodic solutions. The difference between the results of classical and non-classical theories becomes more and more as the dimensions of the system gets close to the length scale parameter. Non-classical theories predict more realistic behaviors for the micro system. The results of this paper can be used in designing microbeam based MEMS devices. 相似文献
89.
Amira Ben Rabeh Faouzi Benzarti Hamid Amiri 《International journal of imaging systems and technology》2017,27(1):3-11
Alzheimer disease is a neurodegenerative disorder that impairs memory, cognitive function, and gradually leads to dementia, physical deterioration, loss of independence, and death of the affected individual. In this context, segmentation of medical images is a very important technique in the field of image analysis and Computer‐Assisted Diagnosis. In this article, we introduce a new automatic method of brain images’ segmentation based on the Active Contour (AC) model to extract the Hippocampus and the Corpus Callosum (CC). Our contribution is to combine the geometric method with the statistical method of the AC. We used the Caselle Level Set and added a learning phase to build an average shape and to make the initialization task automatic. For the step of contour evolution, we used the principle of Level set and we added to it the a priori knowledge. Experimental results are very promising. © 2017 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 27, 3–11, 2017 相似文献
90.
Hela
Gmati Charles Mareau Amine Ammar Saber El Arem 《International journal for numerical methods in engineering》2020,121(15):3362-3381
In the present work, a phase field damage model is developed to address the numerical simulation of brittle fracture. This model successfully captures some important aspects of crack propagation, including crack branching and bifurcation. In addition, the proposed phase field model has been developed in the general framework of anisotropic elasticity. It can thus be used for the simulation of brittle fracture in polycrystalline materials, for which crack propagation is impacted by crystallographic orientation because of the anisotropic character of stiffness properties. 相似文献