Search results for "FREQUENCY"

Koblācija un radiofrekvences ķirurģija otolaringoloģijā. Literatūras apskats un salīdzinoši eksperimenti in vitro

2016

Radiofrekvences un radiofrekvences koblācijas metodes aizvien vairāk tiek pielietotas kā rīkles, tā deguna gliemežnīcu ķirurģijā, tomēr dati par šo procedūru laikā sasniegtajām temperatūrām audos ir skopi. Eksperimentālā pētījuma pirmajā daļā in vitro tika iegūti dati par sasniegtajām temperatūrām koblācijas laikā, kā arī veikta paraugu, ņemtu instrumenta pieskaršanās zonā, histoloģiskā analīze. Cūkas muskuļaudos tika sasniegta 370°C, kamēr submandibulārā dziedzera audos – 320°C temperatūra. Eksperimentālā pētījuma otrajā daļā cūkas deguna gliemežnīcās koblācija tika salīdzināta ar divām citām bipolārām radiofrekvences metodēm, tika iegūti dati par sasniegtajām temperatūrām šo metožu pielie…

On ( p ( x ),  q ( x ))‐Laplace equations in ℝN without Ambrosetti‐Rabinowitz condition

2021

In the present work, we consider a (p(x), q(x))-elliptic equation describing the behavior of a double-phase anisotropic problem which has relevance in electrorheological fluid applications. The analysis leads to the existence of weak (nonnegative) solutions in the special case of potential terms with critical frequency and a superlinear reaction term. In order to prove the existence result, we combine critical point theory of mountain pass type with related topological and variational methods. Basically, the approach is variational, but we do not impose any Ambrosetti-Rabinowitz type condition for the superlinearity of the reaction. More specifically, we apply the Euler-Lagrange functional …

Radiating and non-radiating sources in elasticity

2018

In this work, we study the inverse source problem of a fixed frequency for the Navier's equation. We investigate that nonradiating external forces. If the support of such a force has a convex or non-convex corner or edge on their boundary, the force must be vanishing there. The vanishing property at corners and edges holds also for sufficiently smooth transmission eigenfunctions in elasticity. The idea originates from the enclosure method: The energy identity and new type exponential solutions for the Navier's equation.

Direct image-guided retroperitoneal approach and treatment of the pancreas by using natural orifice transluminal endoscopic surgery after EUS sugar-a…

2021

Novel Energy Efficient Schemes for Wireless Sensor Networks Utilizing Mobile Sensors

2022

Wireless sensor networks (WSNs) facilitate many applications in different fields and are well-known in both academic and industrial areas. The networks mainly include sensors, networking parts and a data processing center to collect data for a variety of purposes. However, the energy consumption problem in the networks is always a critical problem that many researchers are looking for good solutions. In this paper, we propose a data collection method that uses mobile sensors attached with bigger energy storages to collect data from static sensors. In addition, we propose a hybrid energy harvesting scheme to harvest energy from ambient environments to support static sensors to prolong the ne…

New approach for harmonic mitigation in single-phase five-level CHBMI with fundamental frequency switching

2017

The main objective of this paper is to study and analyse the voltage output waveform of a multilevel inverter, to suggest a new approach for harmonic mitigation improving the converter performance. These last type of converters represent a new technology in the field of DC/AC electrical energy conversion, presenting advantages respect to the traditional converters. In fact, the multilevel power converters present a low harmonic content and a high voltage level. The paper considers a five-level single-phase cascaded H-bridge inverter and fundamental frequency modulation techniques. The voltage waveform analysis has allowed to identify a working area of the converter where there are lowest va…

A set of indicators for arc faults detection based on low frequency harmonic analysis

2016

In this paper a novel set of indicators is presented for arc faults detection in electrical circuits. The indicators are defined starting from an experimental characterization of the arc fault phenomenon and the study of the arcing current in several test conditions, which were chosen in accordance with the UL 1699 Standard requirements. The proposed parameters are measured by means of a high resolution low frequency spectral analysis of the arcing current, which allows to achieve a good spectral resolution even with short observation windows.

Testing of “Global Young's Modulus E” on a rehabilitated masonry bell tower in Venice

2017

Abstract This paper shows the effectiveness of the techniques chosen for the rehabilitation of the historic “Sant'Andrea” masonry bell-tower in Venice. The achieved rehabilitation projects based on the indenting technique consisting in removing and replacing bricks in bad conditions, and on the isolation of the bells at the belfry quote, respect all the constraints represented by the aesthetic and structural features of the building. Moreover, the experimental analyses used to define the existing state of the structure are described in detail. The tower is also an interesting case study for the validation of the proposed method to determine the global young's modulus in a rehabilitated maso…

A novel frequency reuse scheme for coordinated multi-point transmission

2010

La transmisión multipunto coordinada (CoMP) se considera en 3GPP LTE-Advanced como una técnica clave para mejorar el rendimiento en el borde de la célula. Con el fin de apoyar la asignación conjunta de asignación de recursos entre células coordinadas en sistemas CoMP, es necesario diseñar esquemas eficientes de reutilización de frecuencias. Sin embargo, la mayoría de los esquemas de reutilización de frecuencias existentes no son adecuados para transmisión CoMP debido a que no consideran el escenario de transmisión conjunta multicelular en su regla de reutilización de frecuencias. Para resolver este problema, en este trabajo se propone un esquema de reutilización de frecuencias que divide el…

A frequency compensation algorithm of four-wheel coherence random road

2013

Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2013/986584 Open access The road surface roughness is the main source of kinematic excitation of a moving vehicle, which has an important influence on vehicle performance. In recent decades, random road models have been widely studied, and a four-wheel random road time domain model is usually generated based on the correlation of the four-wheel input, in which a coherence function is used to describe the coherence of the road input between the left and right wheels usually. However, during our research, there are some conditions that show that…