Simulation of brittle damage for fracture process of endodontically treated tooth

The mechanics of brittle damage in porcelain of an endodontically treated maxilla incisor tooth was simulated using finite element method (FEM). For this purpose a very complex composite structure of endodontically treated tooth is simulated under transverse loading. Three dimensional (3D) model of human maxilla incisor tooth root was developed based on Computed Tomography (CT) scan images. Crown, core cement, resin core, dental post, post cement and dentin were created using SolidWorks software, and then the model was imported into ABAQUS-6.9EF software for nonlinear behavior analysis. This study utilizes finite element method to simulate onset and propagation of crack in ceramic layer (porcelain) by the cause of both tension and compression loading related to complexity of the geometry of tooth implant. The simulation has been done using brittle damaged model available in ABAQUS/Explicit in quasi-static load condition. The load-displacement response of whole structure is measured from the top of porcelain by controlling displacement on a rigid rod. Crack initiated at the top of porcelain bellow the location of the rod caused by tension damage at equivalent load of 590 N. Damage in porcelain accounts for up to 63% reduction of whole structure stiffness from the undamaged state. The failure process in porcelain layer can be described by an exponential rate of fracture energy dissipation. This study demonstrated that the proposed finite element model and analysis procedure can be use to predict the nonlinear behavior of tooth implant

New connection formulae for the q-orthogonal polynomials via a series expansion of the q-exponential

Using a realization of the q-exponential function as an infinite multiplicative sereis of the ordinary exponential functions we obtain new nonlinear connection formulae of the q-orthogonal polynomials such as q-Hermite, q-Laguerre and q-Gegenbauer polynomials in terms of their respective classical analogs.Comment: 14 page

Sdhcare: Secured Distributed Healthcare System

In the healthcare sector, the move towards Electronic Health Records (EHR) systems has been accelerating in parallel with the increased adoption of IoT and smart devices. This is driven by the anticipated advantages for patients and healthcare providers. The integration of EHR and IoT makes it highly heterogeneous in terms of devices, network standards, platforms, types of data, connectivity, etc. Additionally, it introduces security, patient and data privacy, and trust challenges. To address such challenges, this thesis proposes an architecture that combines biometric-based blockchain technology with the EHR system. More specifically, this thesis describes a mechanism that uses a patient’s fingerprint for recovery of patient’s access control on their EHRs securely without compromising their privacy and identity. A secure distributed healthcare system (SDHCARE) is proposed to uniquely identify patients, enable them to control access to, and ensure recoverable access to their EHRs that are exchanged and synchronized between distributed healthcare providers. The system takes into account the security and privacy requirements of Health Insurance Portability and Accountability Act (HIPAA) compliance, and it overcomes the challenges of using secret keys as a patient’s identity to control access to EHRs. The system used distributed architecture with two layers being local to each healthcare provider that is a member of SDHCARE, and two layers shared across all members of SDCHARE system. SDHCARE system was prototyped and implemented in order to validate its functional requirements, security requirements, and to evaluate its performance. The results indicated successful fulfillment of design requirements without significant overhead on the performance as required by healthcare environment

Relaxation of the distribution function tails for systems described by Fokker-Planck equations

We study the formation and the evolution of velocity distribution tails for systems with long-range interactions. In the thermal bath approximation, the evolution of the distribution function of a test particle is governed by a Fokker-Planck equation where the diffusion coefficient depends on the velocity. We extend the theory of Potapenko et al. [Phys. Rev. E, {\bf 56}, 7159 (1997)] developed for power law potentials to the case of an arbitrary potential of interaction. We study how the structure and the progression of the front depend on the behavior of the diffusion coefficient for large velocities. Particular emphasis is given to the case where the velocity dependence of the diffusion coefficient is Gaussian. This situation arises in Fokker-Planck equations associated with one dimensional systems with long-range interactions such as the Hamiltonian Mean Field (HMF) model and in the kinetic theory of two-dimensional point vortices in hydrodynamics. We show that the progression of the front is extremely slow (logarithmic) in that case so that the convergence towards the equilibrium state is peculiar

Direct to consumer advertising via the Internet, a study of hip resurfacing

With increased use of the internet for health information and direct to consumer advertising from medical companies, there is a concern about the quality of the information available for patients. The aim of this study was to examine the quality of health information on the internet for hip resurfacing. An assessment tool was designed to measure quality of information. Websites were measured on credibility of source; usability; currentness of the information; content relevance; content accuracy/completeness and disclosure/bias. Each website assessed was given a total score, based on number of scores achieved from the above categories websites were further analysed on author, geographical origin and possession of an independent credibility check. There was positive correlation between the overall score for the website and the score of each website in each assessment category. Websites by implant companies, doctors and hospitals scored poorly. Websites with an independent credibility check such as Health on the Net (HoN) scored twice the total scores of websites without. Like other internet health websites, the quality of information on hip resurfacing websites is variable. This study highlights methods by which to assess the quality of health information on the internet and advocates that patients should look for a statement of an "independent credibility check" when searching for information on hip resurfacing

Survival Probability for Open Spherical Billiards

We study the survival probability for long times in an open spherical billiard, extending previous work on the circular billiard. We provide details of calculations regarding two billiard configurations, specifically a sphere with a circular hole and a sphere with a square hole. The constant terms of the long-term survival probability expansions have been derived analytically. Terms that vanish in the long time limit are investigated analytically and numerically, leading to connections with the Riemann hypothesis

Exploration of the UAE Native Plants For sustainable Landscaping in Arid Region

In order to maintain sustainability for landscapes in the arid region, the use of native plants is of considerable importance, in the light of the fact that the exotic plants currently used do not resource efficient. The native plants adapted to the harsh environment of the desert ecosystem could play a critical role in this direction where the natural resources could be sustainably used. Research on evaluation and analyzes of native plant species of the UAE for potential application in landscapes have been considered. The present investigation reports the results of the exploration of native plants suited for sustainable landscape for resource efficiency. It also encompasses the study about the response of native grass species identified in the survey and the shrubs to varying levels of irrigation. Further, the germination responses of selected plant species, tissue culture propagation of endangered tree species and their long-term conservation strategies were also part of the study. During plant exploration, 61 plants were identified with potential for landscaping out of which, based on further evaluations with specific landscape qualities, 30 plant species of different forms were recommended for future landscape use. A native grass Digitaria spp. was identified, which was found to have the potential to be used as ground covers in arid landscapes, compared with four nonnative grass species. The analysis and confirmation of stabilized responses for drought tolerance were done based on morphological responses, elemental status and antioxidant enzyme mechanisms operating under wider frequency of irrigation. In 9 selected shrubs and one grass species, irrigation experiment was conducted with a constant irrigation volume under four different frequencies. The responses to induced drought were assessed based on the morphological parameters, macro and micronutrient status that can influence the growth and development. The seeds of fourteen plant species were subjected to germination responses after exogenous application of gibberellic acid at 400 mg/l and 200 mg/l to accelerate germination, where many of the desert species are recalcitrant. The mean germination time (MGT) was shorter, where higher germination is noticed. In vitro propagation protocols were standardized in 3 endangered tree species viz., Moringa peregrina, Haloxylon persicum and Acridocarpus orientalis by direct organogenesis as part of in vitro conservation and faster multiplication. Long-term storage employing cryopreservation by vitrification and desiccation method was accomplished in the above three species. Based on the findings of this study, it can be concluded that the use of native plants of the UAE for landscape applications could create resource efficient, sustainable landscaping

Magnetism of Two Coupled Harmonic Oscillators

The thermodynamical properties of a system of two coupled harmonic oscillators in the presence of an uniform magnetic field B are investigated. Using an unitary transformation, we show that the system can be diagonalized in simple way and then obtain the energy spectrum solutions. These will be used to determine the thermodynamical potential in terms of different physical parameters like the coupling parameter \alpha. This allows us to give a generalization of already significant published work and obtain different results, those could be used to discuss the magnetism of the system. Different limiting cases, in terms of \alpha and B, have been discussed. In fact, quantum corrections to the Landau diamagnetism and orbital paramagnetism are found.Comment: 25 page

Quantum coherence dynamics of displaced squeezed thermal state in a Non-Markovian environment

The dynamical behavior of quantum coherence of a displaced squeezed thermal state in contact with an external bath is discussed in the present work. We use a Fano-Anderson type of Hamiltonian to model the environment and solve the quantum Langevin equation. From the solution of the quantum Langevin equation we obtain the Green's functions which are used to calculate the expectation value of the quadrature operators which are in turn used to construct the covariance matrix. We use a relative entropy based measure to calculate the quantum coherence of the mode. The single mode squeezed thermal state is studied in the Ohmic, sub-Ohmic and the super-Ohmic limits for different values of the mean photon number. In all these limits, we find that when the coupling between the system and the environment is weak, the coherence decays monotonically and exhibit a Markovian nature. When the system and the environment are strongly coupled, we observe that the evolution is initially Markovian and after some time it becomes non-Markovian. The non-Markovian effect is due to the environmental back action on the system. Finally, we also present the steady state dynamics of the coherence in the long time limit in both low and high temperature regime. We find that the qualitative behavior remains the same in both the low and high temperature limits. But quantitative values differ because the coherence in the system is lower due to thermal decoherence.Comment: 20 page