Dependence of chaotic behavior on optical properties and electrostatic effects in double beam torsional Casimir actuation

We investigate the influence of Casimir and electrostatic torques on double beam torsional microelectromechanical systems with materials covering a broad range of conductivities of more than three orders of magnitude. For the frictionless autonomous systems, bifurcation and phase space analysis shows that there is a significant difference between stable and unstable operating regimes for equal and unequal applied voltages on both sides of the double torsional system giving rise to heteroclinic and homoclinic orbits, respectively. For equal applied voltages, only the position of a symmetric unstable saddle equilibrium point is dependent on the material optical properties and electrostatic effects, while in any other case there are stable and unstable equilibrium points are dependent on both factors. For the periodically driven system, a Melnikov function approach is used to show the presence of chaotic motion rendering predictions of whether stiction or stable actuation will take place over long times impossible. Chaotic behavior introduces significant risk for stiction, and it is more prominent to occur for the more conductive systems that experience stronger Casimir forces and torques. Indeed, when unequal voltages are applied, the sensitive dependence of chaotic motion on electrostatics is more pronounced for the highest conductivity systems.Comment: 24 pages, 11 figure

Investigating the effects of smoothness of interfaces on stability of probing nano-scale thin films by neutron reflectometry

Most of the reflectometry methods which are used for determining the phase of complex reflection coefficient such as reference method and Variation of Surroundings medium are based on solving the Schr\"odinger equation using a discontinuous and step-like scattering optical potential. However, during the deposition process for making a real sample the two adjacent layers are mixed together and the interface would not be discontinuous and sharp. The smearing of adjacent layers at the interface (smoothness of interface), would affect the reflectivity, phase of reflection coefficient and reconstruction of the scattering length density (SLD) of the sample. In this paper, we have investigated the stability of reference method in the presence of smooth interfaces. The smoothness of interfaces is considered by using a continuous function scattering potential. We have also proposed a method to achieve the most reliable output result while retrieving the SLD of the sample.Comment: 10 pages, 6 figure

Zero tension Kardar-Parisi-Zhang equation in (d+1)- Dimensions

The joint probability distribution function (PDF) of the height and its gradients is derived for a zero tension $d+1$-dimensional Kardar-Parisi-Zhang (KPZ) equation. It is proved that the height`s PDF of zero tension KPZ equation shows lack of positivity after a finite time $t_{c}$. The properties of zero tension KPZ equation and its differences with the case that it possess an infinitesimal surface tension is discussed. Also potential relation between the time scale $t_{c}$ and the singularity time scale $t_{c, \nu \to 0}$ of the KPZ equation with an infinitesimal surface tension is investigated.Comment: 18 pages, 8 figure

Patients and Health Professionals Views on Caring in Diabetes Disease

Background: Diabetes is a common problem with severe complications. The control of diabetes needs a close and honest relationship between patients and health professionals. The views of these two groups might influence the professional relationship. Objectives: The purpose of this study was to identify the views of diabetic patients versus the views of diabetic care professionals on the content of caring. Patients and Methods: This qualitative study was conducted with the content analysis method. The participants consisted of adults who had suffered from diabetes for a minimum of one year, and health care professionals working in diabetes care centers. Fifteen patients and fifteen health professionals participated in the interviews. Results: The findings present four main themes which are as follows: what caring is and what means to care, the obstacles in providing care, the outcomes of caring, and specialist community-based care as a crucial intervention in diabetes care, the themes were identified and based on the data analysis, It appeared that patients were more outcome centered, while health professionals were more process- centered in the context of caring. Conclusions: It appeared that patients were more outcome centered, while health professionals were more process -centered in the context of caring

Nonlinear actuation of micromechanical Casimir oscillators with topological insulator materials toward chaotic motion:Sensitivity on magnetization and dielectric properties

We have investigated the dynamical actuation of micro-electromechanical systems under the influence of attractive and repulsive Casimir forces between topological insulator plates as a function of their dielectric function and coating magnetization. The analysis of the Casimir force in the limit of strong and weak magnetization shows that the attractive force, which is produced for plate magnetizations in the same direction, is greater than the repulsive force that is produced for opposite magnetizations. However, both forces remain comparable for intermediate magnetizations. Moreover, for weak magnetization, the attractive force becomes stronger for an increasing dielectric function, while the opposite occurs for the repulsive force. On the other hand, increasing magnetization decreases the influence of the dielectric function on both the repulsive and attractive forces. Furthermore, for conservative systems, bifurcation and phase portrait analysis revealed that increasing magnetization decreases the regime of stable operation for devices with attractive forces, while their operation remains always stable under the presence of repulsive forces. Finally, for non-conservative periodically driven systems, the Melnikov function and Poincaré portrait analysis show that for magnetizations in the same direction leading to strong attractive Casimir forces, chaotic motion toward stiction is highly likely to occur preventing the long-term prediction of actuating dynamics. A remedy for this situation is obtained by the application of any magnetization in opposite directions between the interacting surfaces since the repulsive force makes it possible to prevent stiction

Explanatory Model of Diabetes Management; An Experience From Iran

Background: Managing diabetes requires changes in the patients’ life style and health habits which in turn need the comprehensive understanding of the disease and its impact. Objectives: To understand the explanatory model of diabetes in Iran, a qualitative study was performed using the grounded theory method. Patients and Methods: Thirty persons were interviewed: fifteen patients, eleven nurses, three physicians and one dietitian. The semi-structured interviews were transcribed and analyzed in three stages of open, axial and selective coding. Results: The findings showed that patients’ personality can shape their self-care behavior; however, curing, caring and supporting systems are also necessary. The interactions between personality, curing, caring and supporting systems and society makes the outcome, which is the core variable in the designed explanatory model of diabetes. Conclusions: This paper reflects an explanatory model of diabetes management. Understanding the factors that affect self-management behavior is important for nurses as key providers in the health care system