Phase Angle

Research shows that cellular and mitochondrial (ΔΨm) membrane potentials are strong indicators of cellular physiology. In this paper we review further research suggesting that microcurrent frequencies can positively influence both these membrane potentials. The goal of this research is to show how microcurrent might stimulate physiological potentials in order to support a healthy function of bioelectric fields of cells and organs. In the second part of the article, a study to examine the effects of microcurrent application on the body's response to electric measurements is presented, in particular to a change in voltage-current lag known as a phase angle. The test involved measuring bioimpedance of a person before and after a 30-minute application with microcurrent stimulation. Fifteen healthy subjects were examined through impedance measurements taken on one arm. The results showed a consistent increase in phase angle directly after the stimulation, confirming a widely accepted indication of health improvement on a cellular level. These results are encouraging and justify further investigations on the effect of microcurrent stimulation on the human body in relation to general cellular health and regenerative functions.

At the point of common coupling (PCC), the summation of two harmonic voltage vectors at same frequency is only certain if their amplitudes and phase angles are well known. Therefore, there are many cases where the phase angle difference between harmonic voltage vectors is unknown. In practice, for example, in calculating the steady state rating of the a.c. passive harmonic filter, arithmetic summation method is often used in determining maximal harmonic level. This summation law is very conservative as it may result in high cost of equipment ratings. Actually, a compromise should be made in taking into account the equipment safety and the risk of overrating as well as excessive costs. Based on uniform distribution of difference in phase angles, the paper provides an algorithm to calculate the probability upon which the magnitude of summation vector of two harmonic voltages may exceed a given value. On the basis of the probability and the given harmonic value, harmonic summation can be assessed. This may also result in a recommendation of another harmonic summation method for the standard IEC/TR 61000-3-6.

Adequate magnesium (Mg) levels play a vital role in membrane excitability, cell contractility and metabolism, being a key nutrient for sustaining appropriate muscular contraction and performance levels in athletes. Phase angle (PhA), assessed by bioimpedance analysis (BIA), has been reported to be positively associated with most nutritional markers and is an indicator of membrane integrity and water distribution between intra- and extracellular spaces. The aim of the present study was to verify the association between Mg status and PhA as a predictor of cellular health, in a sample of judo athletes from a period of weight stability to prior to competition. Judo athletes (n = 20) from the national team were evaluated on two occasions: during a period when body weight was stable (M1), and prior to competition (M2). Changes between these occasions were calculated as M2-M1. PhA was obtained by bioelectrical impedance spectroscopy at a frequency of 50 KHz. Mg was measured in serum and red blood cells (RBC) by atomic absorption spectrophotometry, and Mg in the diet was assessed from a 24-h diet record over a seven-day period, after an assessment of body composition. Mean PhA did not differ from M1 to M2. However, individual changes in PhA were positively associated with individual changes in serum (r = 0.62, p = 0.004) and RBC Mg (r = 0.45, p = 0.048). This association was independent of weight changes between assessments, but when adjusted for Mg intake changes, only the association between PhA and serum Mg remained significant. These results highlight that in elite athletes PhA may be an indirect indicator of muscular function.

Bioimpedance standards are well established for the normal healthy population and in clinical settings, but they are not available for many sports categories. The aim of this study was to develop reference values for male and female athletes using classic bioimpedance vector analysis (BIVA). In this study, 1556 athletes engaged in different sports were evaluated during their off-season period. A tetrapolar bioelectrical impedance analyzer was used to determine measurements of resistance (R) and reactance (Xc). The classic BIVA procedure, which corrects bioelectrical values for body height, was applied, and fat-free mass, fat mass, and total body water were estimated. In order to verify the need for specific references, classic bioelectrical values were compared to the reference values for the general male and female populations. Additionally, athletes were divided into three groups: endurance, velocity/power, and team sports. In comparison with the general healthy male and female populations, the mean vectors of the athletes showed a shift to the left on the R-Xc graph. Considering the same set of modalities, BIVA confidence graphs showed that male and female endurance athletes presented lower body fluids, fat mass, and fat-free mass than other sets of modalities. This study provides BIVA reference values for an athletic population that can be used as a standard for assessing body composition in male and female athletes.

Adequate magnesium (Mg) levels play a vital role in membrane excitability, cell contractility and metabolism, being a key nutrient for sustaining appropriate muscular contraction and performance levels in athletes. Phase angle (PhA), assessed by bioimpedance analysis (BIA), has been reported to be positively associated with most nutritional markers and is an indicator of membrane integrity and water distribution between intra- and extracellular spaces. The aim of the present study was to verify the association between Mg status and PhA as a predictor of cellular health, in a sample of judo athletes from a period of weight stability to prior to competition. Judo athletes (n = 20) from the national team were evaluated on two occasions: during a period when body weight was stable (M1), and prior to competition (M2). Changes between these occasions were calculated as M2-M1. PhA was obtained by bioelectrical impedance spectroscopy at a frequency of 50 KHz. Mg was measured in serum and re...

This paper presents some fundamental concepts of seismic anisotropy specifically those which have hexagonal symmetry (ordinarily called transversely isotropic in geophysics jargon). There were made calculations of phase and group angles at a planar interface separating an anisotropic media, using routines written in Matlab ® and Maple ® language. The slowness surfaces of the qP, qSV and SH wave, as well as the ray paths in these two media were also estimated. Although only the simplest situations are discussed, this paper is useful as a first step in understanding the fractured media, because it contains examples, software routines, and a reviewing of the basic concepts and formulas of wave propagation.

1Technology Cooperation Agreement: Ecopetrol SA - Instituto Colombiano del Petróleo, AA 4185 Bucaramanga, Santander, Colombia; Universidad Industrial de Santander (UIS) -Petroseismic Group, Bucaramanga, Santander, Colombia 2Geophysical Group, Research Unit, ...

In the present world with the growing demand of electricity the quality of voltage becoming a vital problem. Voltage swell is one of the short term voltage disturbances that occur frequently in power distribution system. Voltage swell characterization is an important, because power quality analysis, troubleshooting, diagnosis, and mitigation policy could be carried out only after characterizing the voltage swells. The magnitude, duration, and phase-angle jump are the essential characteristics of voltage swell are considered in this work. In this paper, MATLAB/SIMULINK with SimPower System is used to simulate the proposed system to show the comparative performance of significant characteristics of voltage swells under power distribution system fault, energizing a capacitor bank and sudden switching off a heavy linear and nonlinear load.

1Technology Cooperation Agreement: Ecopetrol SA - Instituto Colombiano del Petróleo, AA 4185 Bucaramanga, Santander, Colombia; Universidad Industrial de Santander (UIS) -Petroseismic Group, Bucaramanga, Santander, Colombia 2Geophysical Group, Research Unit, ...

OBJECTIVES: The aim of this study was to evaluate the association between phase angle, body composition, and blood glucose changes in healthy young males after 6 months of physical training.
METHODS: Volunteers, 98 healthy males (18.8 ± 0.5 years), had 6 months of progressive physical training (5 days a week, 90 minutes a day). Resistance, reactance, and phase angle were obtained by bioelectrical impedance analysis, body composition (fat mass, bone mineral content [BMC], and lean soft tissue [LST]) by dual-energy X-ray absorptiometry, and blood glucose by reflectance photometry. Measurements were made at rest and in a fasted state, both before and after the training period.
RESULTS: Phase angle, reactance, BMC, and LST significantly increased (0.6°, 3.8 Ω, 0.1 kg, and 1.9 kg, respectively; P < .01), whereas resistance and blood glucose decreased (-11.2 Ω and -4.1 mg/dL; P < .01). Changes in resistance and reactance explained those changes observed in LST (R2 = .26 and .16, respectively), but phase angle changes were not related to body composition and blood glucose alterations (P < .05).
CONCLUSIONS: A 6-month period of physical training was associated with positive changes in phase angle, body composition, and blood glucose in healthy young males, reinforcing the importance of maintaining a physically active lifestyle.

Cartel presentado por Ricardo Rendón-Rodríguez ante el comité científico en el Congreso Nacional de Nutrición Clínica por la Asociación Mexicana de Nutrición Clínica y Terapia Nutricional A.C.  (AMAEE)y Universidad Anáhuac México. Celebrado del 6 al 9 de Octubre del 2016 en la ciudad de Acapulco, Guerrrero. México.

Representando a: Instituto Nacional de Enfermedades Respiratorias (INER). Centro de Investigación en Enfermedades Infecciosas (CIENI)

Autor: Rendón-Rodríguez R.
Co-autores: Osuna-Padilla IA.  Aguilar-Vargas A. Villazón-De la Rosa A. Reyes-Terán G.

Pre-arcing stage is the first working step in high breaking capacity (HBC) fuse operation and affects the following step, namely, the arcing step. We have performed realistic HBC fuse tests for short (10 ms) pre-arcing times by varying the phase angle of the electrical fault (defined as the phase angle of the fault current once the supplied voltage is applied

The aims of this study were to analyze the usefulness of raw bioelectrical impedance (BI) parameters in assessing water compartments and fluid distribution in athletes. A total of 202 men and 71 female athletes were analyzed. Total body water (TBW) and extracellular water (ECW) were determined by dilution techniques, while intracellular water (ICW) was calculated. Fluid distribution was calculated as the ECW/ICW ratio (E:I). Phase angle (PhA), resistance (R) and reactance (Xc) were obtained through BI spectroscopy using frequency 50kHz. Fat (FM) and fat-free mass (FFM) were assessed by dual-energy X-ray absorptiometry. After adjusting for height, FM, FFM, age and sports category we observed that: PhA predicted ICW (females: β = 1.62, p &lt; 0.01; males: β = 2.70, p &lt; 0.01) and E:I (males and females: β = -0.08; p &lt; 0.01); R explained TBW (females: β = -0.03; p &lt; 0.01; males: β = -0.06; p &lt; 0.01) and ECW (females: β = -0.02, p &lt; 0.01; males: β = -0.03, p &lt; 0.01) and...

Adequate magnesium (Mg) levels play a vital role in membrane excitability, cell contractility and metabolism, being a key nutrient for sustaining appropriate muscular contraction and performance levels in athletes. Phase angle (PhA), assessed by bioimpedance analysis (BIA), has been reported to be positively associated with most nutritional markers and is an indicator of membrane integrity and water distribution between intra- and extracellular spaces. The aim of the present study was to verify the association between Mg status and PhA as a predictor of cellular health, in a sample of judo athletes from a period of weight stability to prior to competition. Judo athletes (n = 20) from the national team were evaluated on two occasions: during a period when body weight was stable (M1), and prior to competition (M2). Changes between these occasions were calculated as M2-M1. PhA was obtained by bioelectrical impedance spectroscopy at a frequency of 50 KHz. Mg was measured in serum and re...

ABSTRACT All characterization of asphalt mixtures must begin with the properties of the mixture in an undamaged state. Subsequent tests of the mixture in different stress or strain states at a level to cause damage can be referred to this undamaged state to assess the degree to which the mixture has been changed. All forms of such change from an original state by such damaging processes as fatigue, plasticity, healing, moisture damage, and aging can only be properly assessed by comparison with an accurately measured undamaged state. This is particularly the case with the use of pseudostrain dissipated energy to characterize the departure of a material from an original linear viscoelastic state. This paper presents a new test and data analysis protocol based on linear viscoelasticity theory to characterize the master curves of the viscoelastic properties of an asphalt mixture. Instead of running a relaxation modulus test in which controlling the test apparatus is a serious challenge, the proposed test protocol applied a uniaxial monotonically increasing tensile stress to the test specimen. The axial and radial deformations of the specimen were recorded and used to calculate the axial and radial strains. The uniaxial tensile loading rate and time were carefully controlled to assure that the strain of the specimen was limited to the small-strain condition (&amp;lt; 100 mu epsilon) under which the specimen was assumed not to be damaged during the test. The applied stress and measured strain were fitted with functions of time. Applying the Laplace transform to the stress and strain functions, the relaxation modulus as a function of time was determined using the Boltzmann superposition principle and the convolution theorem. The relation between the relaxation modulus and the complex modulus was used to determine the complex modulus as a complex function of frequency. Then the magnitude and phase angle of the complex modulus were obtained from the real part and imaginary part of the complex modulus. The proposed test and data analysis protocol were performed on the same specimen at three temperatures, 10, 20, and 30 degrees C, so master curves of the magnitude and phase angle of the complex modulus were constructed using the time-temperature superposition principle. The master curves of the magnitude and phase angle of the complex modulus were fitted with mathematical functions that were reported in the literature and were modified to be more comprehensive. The parameters in the mathematical functions were searched simultaneously using the Solver Function built into the Microsoft Excel. Compared to the traditional relaxation modulus and the dynamic modulus test protocols, the newly developed test protocol was more efficient to characterize the viscoelastic properties of asphalt mixtures. The newly developed test method did not introduce any damage to the specimen so the same specimen may be retested for its fatigue, healing, and other properties.