Free vibration of thin-walled composite shell structures reinforced with uniform and linear carbon nanotubes: Effect of the elastic foundation and nonlinearity

In this work, we discuss the free vibration behavior of thin-walled composite shell structures reinforced with carbon nanotubes (CNTs) in a nonlinear setting and resting on a Winkler– Pasternak Foundation (WPF). The theoretical model and the differential equations associated with the problem account for different distributions of CNTs (with uniform or nonuniform linear patterns), together with the presence of an elastic foundation, and von-Karman type nonlinearities. The basic equations of the problem are solved by using the Galerkin and Grigolyuk methods, in order to determine the frequencies associated with linear and nonlinear free vibrations. The reliability of the proposed methodology is verified against further predictions from the literature. Then, we examine the model for the sensitivity of the vibration response to different input parameters, such as the mechanical properties of the soil, or the nonlinearities and distributions of the reinforcing CNT phase, as useful for design purposes and benchmark solutions for more complicated computational studies on the topic

Traumatic neuroma after torticollis surgery: a rare occurrence

We report a 15 years old girl who admitted to our hospital with signs of recurrent torticollis after two failed operations and consistent pain at the side of surgery. The past operations were performed at 1 and 6 years of age and she has been suffering pain from previous incisions with neck movements. At physical examination, the sternocleidomastoid (SCM) muscle behaved like a fibrous band, restricting the neck movements and resulting in pain. The operation was indicated for the fibrotic SCM. At operation two separate incisions were performed on each end of the SCM to remove all of the fibrotic muscle. The histopathological examination demonstrated a traumatic neuroma which respectively correlates with the pain symptoms. The patient discharged on the second postoperative day and physiotherapy was started. The patient is symptom free one year after the surgery. This case demonstrates a rare occurrence of traumatic neuroma after torticollis surgery, which can manifest with pain.Keywords: neuroma, torticollis, traum

Operation of Faddeev-Kernel in Configuration Space

We present a practical method to solve Faddeev three-body equations at energies above three-body breakup threshold as integral equations in coordinate space. This is an extension of previously used method for bound states and scattering states below three-body breakup threshold energy. We show that breakup components in three-body reactions produce long-range effects on Faddeev integral kernels in coordinate space, and propose numerical procedures to treat these effects. Using these techniques, we solve Faddeev equations for neutron-deuteron scattering to compare with benchmark solutions.Comment: 20 pages, 8 figures, to be published in Few-Body System

Thinking about Eating Food Activates Visual Cortex with Reduced Bilateral Cerebellar Activation in Females with Anorexia Nervosa: An fMRI Study

Background: Women with anorexia nervosa (AN) have aberrant cognitions about food and altered activity in prefrontal cortical and somatosensory regions to food images. However, differential effects on the brain when thinking about eating food between healthy women and those with AN is unknown. Methods: Functional magnetic resonance imaging (fMRI) examined neural activation when 42 women thought about eating the food shown in images: 18 with AN (11 RAN, 7 BPAN) and 24 age-matched controls (HC). Results: Group contrasts between HC and AN revealed reduced activation in AN in the bilateral cerebellar vermis, and increased activation in the right visual cortex. Preliminary comparisons between AN subtypes and healthy controls suggest differences in cortical and limbic regions. Conclusions: These preliminary data suggest that thinking about eating food shown in images increases visual and prefrontal cortical neural responses in females with AN, which may underlie cognitive biases towards food stimuli and ruminations about controlling food intake. Future studies are needed to explicitly test how thinking about eating activates restraint cognitions, specifically in those with restricting vs. binge-purging AN subtypes

Abstract Estimation of the Parameters of Skewed-Stable Distributions

Stable distributions have received great interest over the last few years in the signal processing community and have proved tobe strong alternatives to the Gaussian distribution. There have been several works in the literature addressing the problem of estimating the parameters of stable distributions. However, most of these works consider only the special case of symmetric stable random variables. This is an important restriction though, since most real life signals are skewed. Previous work on estimating the parameters of general (possibly skewed) stable distributions has been limited. The existing techniques are either computationally too expensive or their estimates have high variances. In this paper, we solve the general problem of stable parameter estimation analytically. We introduce three novel classes of estimators for the parameters of general stable distributions. These new classes of estimators are based on formulas we have developed for the fractional and negative order moments of skewed stable random variables. These are generalisations of methods previously suggested forparameter estimation with symmetric stable distributions. Of all known techniques for the general problem, only the characteristic function technique and the methods we have suggested yield closed form estimates for the parameters which may be e ciently computed. Simulation results show that at least one of our new estimators has better performance than the characteristic function technique over most of the parameter space. Furthermore our techniques require substantially less computation.