Influence of surface-bound water on the electrophysical properties of MW– CNTs

This report is devoted to the investigation of a dispersed water / multiwalled carbon nanotubes system, from various degrees of humidity. Adsorption electrophysical and calorimetric behavior features of such systems are considered. The studies presented in this paper make it possible to reveal the characteristic behavior features of thin water films on the surface MWCNTs in a wide range of temperatures and frequencies. Particularly significant are the results in the area of phase transitions, which makes it possible to characterize the state of water as a bound state

Investigation electrophysical properties of allotropic modifications of carbon in the range of temperatures 140-400 K

The paper presents the results of the investigation allotropic modifications of carbon (coal, graphite, fullerenes, CNTs Dependences of conductivity on the field frequency in the temperature range 140-400 ◦K are presented. The characteristic features associated with the structure and types of hybridization are revealed. Calculation of the activation energy of carriers was performed

Investigation of activative conductivity in CNT and F-CNT in the range of temperatures 140-470 ◦K

In the work by the method of dielectric relaxation spectroscopy, activation of p-electronic orbitals in CNT and F–CNT was investigated. The activation energy of carriers in different range was estimated. Dependences of conductivity and dielectric losses on the frequency of the alternating field in the temperature range 140–470 K are presented

INVESTIGATION OF CAVITATION AND ELECTROCORROSIVE DESTRUCTION OF MATERIALS FOR SCREW SCREWS AND SHAFTS IN HYDRODYNAMIC MEDIA

This report is devoted to the study of nucleation and evolution of defects on the bronze surface by means of cavitation and electrochemical corrosion. The studies were carried out using electronic and scanning probe microscopy

Economic recession and long-term care. A scoping study

Despite its obvious appeal, the concept of public involvement is poorly defined and its rationale and objectives are rarely specified when applied to current health policy contexts. This paper explores some of the underlying concepts, definitions, and issues underpinning public involvement policies and proposes a set of criteria and questions that need to be addressed to allow for the evaluation of public involvement strategies and their impact on the health policy process. It aims to further our understanding of the role that public involvement may play in contributing to health systems that are responsive to the needs and priorities of the public, and, ultimately, providing better health and health care services to the community at large

CT angiographic study of the role of both willis circle and vertebral arteries during selective cerebral perfusion - a study in 105 patients

Unilateral selective cerebral perfusion (SCP) is a method for cerebral protection in aortic arch surgery. However, variations of the circle of Willis (CoW) could vitiate its protective effect. The aim of our present work was to prospectively analyze variations of CoW and vertebral arteries using CT angiography. From January, 2008 to July, 2008, a total of 105 consecutive patients underwent CT-angiography of the CoW in the Division of Radiology, St. Ekaterina University Hospital of Sofia. There were at least six CoW configurations that could lead to significant hypo perfusion during unilateral SCP: i) type IA - hypoplasia or absence of left posterior communicating artery (PComA) (in 41.9% of the patients); ii) type IB - hypoplasia or absence of anterior communicating artery (AComA) (in 1.9%); iii) type IIA - hypoplasia or absence of both left PComA and AComA (in 6.67%); iv) type IIB - hypoplasia or absence of left P1 or right vertebral artery (VA) (in 6.67%); v) type III - hypoplasia or absence of right A1 (in 8.57%), and vi) type IV - hypoplasia or absence of both right A1 and right VA or both right A1 and left PComA (in 0.95%). All these types were present in a 66.67% of all the examined patients. Our present study showed that CoW variations are presented in significant number of patients. These results support the need of extensive preoperative examination and meticulous intraoperative monitoring of cerebral perfusion during unilateral SCP.Scripta Scientifica Medica 2012; 44(2): 73-77