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.

Presently exploited rates of fossil fuels are expected to deplete resources within the next 40-50 years, and consequently, human beings seek alternative energy resources that are clean, friendly to the environment and sustainable. Accumulation of carbon dioxide in the lower layers of the atmosphere may cause climate change and consequent occurrence of floods, intensive rainfalls and droughts. In order to reduce such dangerous effects all countries have to try to improve their energy resources quality and, if possible, to replace fossil fuels, such as coal, with the renewable alternatives of wind, solar and solar-hydrogen energies. Among these, wind power has a priori significance for Turkey. Wind time series depend very much on meteorological measurements of wind direction and velocity. Unfortunately, in many parts of the world, it is difficult to obtain such data for wind speed time series assessments. In this study, harmonic analysis is used to model the daily wind speed values recorded at ten stations in the Marmara region, Turkey, with distinct meteorological conditions from 1993 to 1997. The coefficients, amplitude, variance and phase angle, of each harmonic are calculated for the months of January, April, July and October, leading to total variance maps for spatial interpolations. It is seen that up to the 9th harmonic more than 80% of the total variance can be presented. The western and eastern parts of the Marmara region have different wind pattern characteristics. The contributions of each harmonic to the total variance are calculated, and then regional variance maps are evaluated.

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.

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 < 0.01; males: β = 2.70, p < 0.01) and E:I (males and females: β = −0.08; p < 0.01); R explained TBW (females: β = −0.03; p < 0.01; males: β = −0.06; p < 0.01) and ECW (females: β =-0.02, p < 0.01; males: β = −0.03, p < 0.01) and ICW (females: β =-0.01, p < 0.053; males: β =-0.03 p < 0.01); and Xc predicted ECW (females: β = −0.06, p < 0.01; males: β = −0.12, p < 0.01). A higher PhA is a good predictor of a larger ICW pool and a lower E:I, regardless of body composition, age, height, and sports category. Lower R is associated with higher water pools whereas ECW expansion is explained by lower Xc. Raw BI parameters are useful predictors of total and extracellular pools, cellular hydration and fluid distribution in athletes.

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, ...

Vector length as a proxy for the adequacy of ultrafiltration in hemodialysis. Background. Evaluation of dialysis adequacy has focused on parameters of solute (principally urea) clearance. Relatively little attention has been paid to the adequacy of ultrafiltration. At a given phase angle, the bioimpedance vector length reflects the degree of tissue hydration, as the vector lengthens with ultrafiltration. Methods. We determined the relative risk of death associated with different bioimpedance vector lengths in a 3009 patient hemodialysis cohort using proportional hazards regression. Results. The mean phase angle was 4.8 • , and the mean vector length 300 ± 70 ohm/m (range 140 to 630 ohm/m). Vector length was much longer in women than men (mean 340 vs. 270 ohm/m) and significantly longer in African Americans and patients without diabetes. Adjusted for the effects of age, gender, race, diabetes, vintage, weight, albumin, prealbumin, creatinine, hemoglobin, ferritin, and dialysis dose, the relative risk (RR) of death was 0.75 (95% CI 0.57 to 0.88) per 100 ohm/m decrease in vector length. The effect of vector length on RR was somewhat more pronounced among men (vector length × gender interaction, P = 0.07). Considering vector length of 300 to 350 ohm/m as the referent category, the RRs of death were 1.54 (95% CI 1.08 to 2.21) and 2.83 (95% CI 1.55 to 5.14) for patients with vector length 200 to 250 and <200 ohm/m, respectively. Conclusion. Shorter predialysis bioimpedance vectors, indicating greater soft tissue hydration, were associated with diminished survival in hemodialysis patients. These findings validate clinical observations linking longevity to maintenance of dry body weight. The evaluation of hemodialysis adequacy has focused on parameters of solute (principally urea) clearance.

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, ...

T his 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.

A quantizer for complex data is defined by a partition of the complex plane and a representation point associated with each cell of the partition. A polar coordinate quantizer independently quantizes the magnitude and phase angle of complex data. We derive design equations for minimum mean-squared error polar coordinate quantizers and report some interesting theoretical results on their performance, including performance limits for "phase-only" representations. The results provide a concrete example of a biased estimator whose mean-squared error is smaller than that of any unbiased estimator. Quantizer design examples show the relative importance of magnitude and phase encoding.

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.

Motivation-The study examined whether experts and novices differed in their recognition of decisionmaking cues. Research approach-To test cue recognition, the authors developed and tested a computer-based cue recognition task on a group of expert and novice offender profilers. Findings/Design-Recognition performance was assessed in relation to cue classification agreement and recognition response latency among and between the two groups. The findings revealed superior performance on both measures by the experts compared to the novices. Research limitations/Implications-The findings have implications for the cue selection process in the design of computer-based training, and decision support systems. Originality/Value-The research offers an objective means of: 1) identifying cues; 2) gauging relative cue stability/strength; 3) comparing cue recognition across expertise; and, 4) selecting a valid cue-set for use in training and support systems. Take away message-There are significant differences in cue recognition across expertise that may, in part, differentiate decision-making performance.

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 study explores correlation between chemistry and rheology of aged PMA. Severity of aging procedure, polymer content and its concentration affect PMA viscosity. Complex shear modulus can be fairly estimated from chemical composition elucidated by ATR FT-IR. Polymer concentration can be backcalculated from absorbance spectrum of PMA.

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...

To define whether reference values for bioimpedance analysis (BIA) can be predicted in healthy individuals, individual characteristics and BIA variables (resistance index=height 2 /parallel resistance and reactance index= height 2 /parallel reactance) were evaluated in non-obese healthy individuals: 863 men and 769 women with an age range 20-70 years and body mass index (BMI) 19.0-29.9 kg/m 2. The following predictive equations were obtained using multiple regression analysis: Resistance index (cm 2 /ohm) Males 21.06 + 0.087xage + 1.091xweight-1.801xBMI, Females 20.35 + 0.037xage + 0.878xweight-1.343xBMI Reactance index (cm 2 /ohm) Males 0.57 + 0.117xweight-0.096xBMI Females 1.42 + 0.078xweight-0.075xBMI In conclusion, reference BIA values seem to be reasonably predicted based on individual characteristics.

We prove a multiplicity result for a class of strongly indefinite nonlinear second order asymptotically linear systems with Dirichlet boundary conditions. The key idea for the proof is to bring together the classical shooting method and the Maslov index of the linear Hamiltonian systems associated to the asymptotic limits of the given nonlinearity. 2000 Mathematics Subject Classification. 34B15, 37J05, 53C50. Key words and phrases. Multiplicity, Asymptotically linear BVP, Maslov index, phase angle. The work of the first two authors has been performed in the frame of the Italian M.I.U.R. project "Variational and topological methods in the study of nonlinear phenomena" and of the Italian GNAMPA-I.N.d.A.M. project "Nonlinear analysis techniques for boundary value problems associated to differential equations". The third author was partially supported by Italian M.I.U.R. project "Variational Methods and Nonlinear Differential Equations".

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 < 0.01; males: β = 2.70, p < 0.01) and E:I (males and females: β = −0.08; p < 0.01); R explained TBW (females: β = −0.03; p < 0.01; males: β = −0.06; p < 0.01) and ECW (females: β =-0.02, p < 0.01; males: β = −0.03, p < 0.01) and ICW (females: β =-0.01, p < 0.053; males: β =-0.03 p < 0.01); and Xc predicted ECW (females: β = −0.06, p < 0.01; males: β = −0.12, p < 0.01). A higher PhA is a good predictor of a larger ICW pool and a lower E:I, regardless of body composition, age, height, and sports category. Lower R is associated with higher water pools whereas ECW expansion is explained by lower Xc. Raw BI parameters are useful predictors of total and extracellular pools, cellular hydration and fluid distribution in athletes.

Properties of bioelectrical impedance analysis (BIA) reflect body-composition and may serve as stand-alone indicators of maternal health. Despite these potential roles, BIA properties during pregnancy and lactation in rural South Asian women have not been described previously, although pregnancy and infant health outcomes are often compromised. This paper reports the BIA properties among a large sample of pregnant and postpartum women of rural Bangladesh, aged 12-46 years, participating in a substudy of a communitybased, placebo-controlled trial of vitamin A or beta-carotene supplementation. Anthropometry and single frequency (50 kHz) BIA were assessed in 1,435 women during the first trimester (≤12 weeks gestation), in 1,237 women during the third trimester (32-36 weeks gestation), and in 1,141 women at 12-18 weeks postpartum. Resistance and reactance were recorded, and impedance and phase angle were calculated. Data were examined cross-sectionally to maximize sample-size at each timepoint, and the factors relating to BIA properties were explored. Women were typically young, primiparous and lacking formal education (22.2±6.3 years old, 42.2% primiparous, and 39.7% unschooled among the first trimester participants). Weight (kg), resistance (Ω), and reactance (Ω) were 42.1±5.7, 688±77, and 73±12 in the first trimester; 47.7±5.9, 646±77, and 64±12 in the third trimester; and 42.7±5.6, 699±79, and 72±12 postpartum respectively. Resistance declined with age and increased with body mass index. Resistance was higher than that observed in other, non-Asian pregnant populations, likely reflecting considerably smaller body-volume among Bangladeshi women. Resistance and reactance decreased in advanced stage of pregnancy as the rate of gain in weight increased, returning to the first trimester values by the three months postpartum. Normative distributions of BIA properties are presented for rural Bangladeshi women across a reproductive cycle that may be related to pregnancy outcomes and ultimately be used for assessing body-composition in this population.

Properties of bioelectrical impedance analysis (BIA) reflect body-composition and may serve as stand-alone indicators of maternal health. Despite these potential roles, BIA properties during pregnancy and lactation in rural South Asian women have not been described previously, although pregnancy and infant health outcomes are often compromised. This paper reports the BIA properties among a large sample of pregnant and postpartum women of rural Bangladesh, aged 12-46 years, participating in a substudy of a communitybased, placebo-controlled trial of vitamin A or beta-carotene supplementation. Anthropometry and single frequency (50 kHz) BIA were assessed in 1,435 women during the first trimester (≤12 weeks gestation), in 1,237 women during the third trimester (32-36 weeks gestation), and in 1,141 women at 12-18 weeks postpartum. Resistance and reactance were recorded, and impedance and phase angle were calculated. Data were examined cross-sectionally to maximize sample-size at each timepoint, and the factors relating to BIA properties were explored. Women were typically young, primiparous and lacking formal education (22.2±6.3 years old, 42.2% primiparous, and 39.7% unschooled among the first trimester participants). Weight (kg), resistance (Ω), and reactance (Ω) were 42.1±5.7, 688±77, and 73±12 in the first trimester; 47.7±5.9, 646±77, and 64±12 in the third trimester; and 42.7±5.6, 699±79, and 72±12 postpartum respectively. Resistance declined with age and increased with body mass index. Resistance was higher than that observed in other, non-Asian pregnant populations, likely reflecting considerably smaller body-volume among Bangladeshi women. Resistance and reactance decreased in advanced stage of pregnancy as the rate of gain in weight increased, returning to the first trimester values by the three months postpartum. Normative distributions of BIA properties are presented for rural Bangladeshi women across a reproductive cycle that may be related to pregnancy outcomes and ultimately be used for assessing body-composition in this population.

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.

Texture and rheology properties of fatty acid salt-fatty acid mixture stabilized oil-water (o/w) emulsions are being explored. While NaOH solution was introduced as aqueous phase, oil phase contained in it dissolved lauric acid. When these oil and water phases are brought in contact, a portion of lauric acid transforms into sodium laurate in situ via acid-base reaction, the combination of which at a certain threshold concentration and above is believed to act as emulsifier in stabilizing the given o/w emulsion system. Light microscopy under cross polarizing conditions suggested that in addition to the formation of surfactant stabilized emulsion droplets, formation of molecular aggregates of vesicle type is imminent in these conditions, both the size and number density of which is found to be a function of emulsifier concentration ratio. The concentration of emulsifier (sodium laurate-lauric acid) is being assessed in this work indirectly as a function of NaOH concentration, due to the problem associated with its quantification. Non or a very small number of vesicles was observed at NaOH concentration below 0.4 M, whilst in the presence of 0.4-0.8 M NaOH the vesicle population increased substantially. While vesicle population density decreased past 0.8 M NaOH, their size increased with NaOH concentration from 0.8 to 1 M. These observations suggested that sodium laurate-lauric acid concentration ratio that corresponds to 0.6-0.8 M NaOH is the optimum NaOH concentration at which maximum vesicle number density is observed. As far as rheology properties are concerned, at any givenγ, in the absence of NaOH, the η of the oil solubilized lauric acid was found to be much lower than the η of corresponding sodium laurate-lauric acid stabilized o/w emulsion. Though η(γ) profiles of sodium laurate-lauric acid stabilized o/w emulsion was not a linear function under the given sets of experimental conditions, at all conditions η strongly depended on sodium laurate-lauric acid concentrations (concentration of NaOH in this case). What more is that at any givenγ, the η was observed to be maximum at sodium laurate-lauric acid concentration ratio that corresponded to 0.8 M NaOH, a situation which corresponds to the presence of the maximum vesicle number density. In addition to η, in the presence of 0.8 M NaOH, higher values of σ Y was observed, implying that at this particular NaOH concentration these emulsions possessed greater degree of emulsion structuring compared to other NaOH concentrations. These observations lead to the conclusion that sodium laurate concentration plays a great role in the formation of fatty acid salt vesicles, that under the given set of conditions sodium laurate-lauric acid concentration corresponding to 0.8 M NaOH is the optimum concentration at which maximum number of vesicles are produced, and that rheology property of these emulsions depend not only on emulsion droplets but also on the vesicle number density and size. Test on oscillatory shear mode also suggested that much like o/w emulsions stabilized with other type surfactant, the viscoelastic properties of these sodium laurate-lauric acid stabilized o/w emulsions depended highly on surfactant concentration. The fact that G response was dominant over G response at all measured frequency and sodium laurate-lauric acid concentration, it is evident that viscous property dominated over elastic property in these emulsion. The good news is that improved elastic property is observed at sodium laurate-lauric acid concentration that corresponded to 0.6-0.8 M NaOH. And not only, in the presence of 0.8 M NaOH, while G response of these samples was dominant over G response at low domain, the dynamic moduli crossed-over at around 2 Hz, past which the G response became dominant over G. This implies that, at this particular surfactant concentration, emulsions stabilized with sodium laurate-laurate mixture displays an excellent viscoelastic property pertaining to emulsions used in pharmaceutical and cosmetic products. This further suggests that in the presence of 0.8 M NaOH these o/w emulsion both spread easily and stabilized better as well as possess long storage stability and shelf life. With these dynamic moduli responses it is not surprising that the δ of these sodium laurate-lauric acid stabilized emulsions decreased with NaOH concentration from 0.4 to 0.8 M. The fact that these emulsion showed smallest δ in the presence of 0.8 M NaOH as opposed to other NaOH concentrations, it is evident that solid-like elastic property of these emulsions

Properties of bioelectrical impedance analysis (BIA) reflect body-composition and may serve as stand-alone indicators of maternal health. Despite these potential roles, BIA properties during pregnancy and lactation in rural South Asian women have not been described previously, although pregnancy and infant health outcomes are often compromised. This paper reports the BIA properties among a large sample of pregnant and postpartum women of rural Bangladesh, aged 12-46 years, participating in a substudy of a communitybased, placebo-controlled trial of vitamin A or beta-carotene supplementation. Anthropometry and single frequency (50 kHz) BIA were assessed in 1,435 women during the first trimester (≤12 weeks gestation), in 1,237 women during the third trimester (32-36 weeks gestation), and in 1,141 women at 12-18 weeks postpartum. Resistance and reactance were recorded, and impedance and phase angle were calculated. Data were examined cross-sectionally to maximize sample-size at each timepoint, and the factors relating to BIA properties were explored. Women were typically young, primiparous and lacking formal education (22.2±6.3 years old, 42.2% primiparous, and 39.7% unschooled among the first trimester participants). Weight (kg), resistance (Ω), and reactance (Ω) were 42.1±5.7, 688±77, and 73±12 in the first trimester; 47.7±5.9, 646±77, and 64±12 in the third trimester; and 42.7±5.6, 699±79, and 72±12 postpartum respectively. Resistance declined with age and increased with body mass index. Resistance was higher than that observed in other, non-Asian pregnant populations, likely reflecting considerably smaller body-volume among Bangladeshi women. Resistance and reactance decreased in advanced stage of pregnancy as the rate of gain in weight increased, returning to the first trimester values by the three months postpartum. Normative distributions of BIA properties are presented for rural Bangladeshi women across a reproductive cycle that may be related to pregnancy outcomes and ultimately be used for assessing body-composition in this population.