Ethanol Mass Concentration Research Articles

Adequate assessment of linear function of calibration according to GOST R ISO 11095-2007 for ethanol mass concentration measurement

To assess the adequacy of linear function of calibration according to GOST R ISO 11095-2007 for ethanol mass concentration measurement using internal reference materials (RMs). An experiment on calibration in accordance with the GOST R ISO 11095-2007 National standard of the RF was carried out using internal RMs, namely aqueous solutions of ethanol at different concentrations. Measurements were performed for two subbands of ethanol concentrations at RMs: 0.15-1.05 and 1.0-7.0 mg/ml - according to the certified methodology. The graphs of the calibration's functions based on experimental data are consistent with the assumption of the calibration function's linearity, as well as the assumption of the standard deviation's constance of residues is equitable for two subbands of RMs. Proven linear models in the calibration experiment may be recommended for use in the ethanol mass concentration measurement.

Experimental investigation on heat transfer performance during electrospray cooling with ethanol–R141b mixture

Electrospray (ES) cooling is promising to achieve energy-efficient liquid atomization and high-heat-flux thermal dissipation at relatively low operating temperatures (<75 °C) when using an ethanol–R141b mixture as a coolant, making it suitable for micro-sized electronics. Nevertheless, there has been little research on ES cooling using the ethanol–R141b mixture. This paper presents an experimental investigation on the cooling performance triggered by ES impingement. Results demonstrate that adding ethanol to R141b improves the electrohydrodynamic (EHD) atomization, namely reducing Sauter mean diameter and increasing spray angle. Meanwhile, it also causes the deposition of large-size isolated liquid films on the surface. As the mass concentration of ethanol increases from 10% to 60%, the cooling performance in terms of the temperature drop (Ts,d) and time-averaged heat transfer coefficient (hm), first increases and then decreases or almost remains unchanged. This is a complicated consequence of microscopic droplet behaviors, film deposition, and thermal properties, which are dependent on the mass concentration of ethanol. For volumetric flow rates of 100 and 150 mL/h, the ES sprays with mass fractions of 50% and 20% produce preferable cooling capabilities with respective hm equivalent to 1.6 and 1.9 kW/(m2·K) under the current tests. A Nusselt number correlation with the electric Weber, hydrodynamic Weber, and Prandtl numbers is derived. This correlation covers more than 97.7% of the experimental data within a ± 15% deviation. The derived correlation implies the increase in the flow rate has a superior contribution to the heat transfer in comparison with the applied voltage.

Heat transfer in a round channel with circulation of a non-azeotropic mixture

Mixtures are widely used as refrigerants and heat carriers in various energy systems. When a non-azeotropic mixture boils, a light-boiling component releases intensively, which leads to a change in its concentration both in the liquid and vapor phases. The studies were carried out using a non-azeotropic alcohol-water mixture with a mass concentration of ethanol of 20% in a round stainless steel channel. The inner diameter of the channel was 7.6 mm; the wall thickness was 0.2 mm. In this series of experiments, the absolute pressure in the vessel was maintained within 0.050.001 MPa. The range of liquid mass flow rates through the channel was 44–46 kg/m2s; the heat flux density was 1260–11981 W/m2. The wall temperature was measured at 10 points on the lower generatrix of the channel and at 3 points on the upper generatrix. It is shown that with a phase transition, the heat transfer coefficient on the upper generatrix of the channel is significantly higher than that on the lower generatrix of the channel. The heat transfer coefficient on the lower generatrix in the single-phase flow is approximately twice as high as in the two-phase flow.

Metrological traceability of the breath alcohol measurements

Breath alcohol measurements are widely used worldwide to detect the presence of alcohol in the human body. For those measurements, different metrological traceability chains are used, both in the international normative documents and at the national level. Different measurement standards used to calibrate breath analysers reproduce different quantities: on the one hand, an «actual» ethanol mass concentration, and, on the other hand, the operationally defined «ethanol mass concentration by Dubowski (or Harger)». This makes the comparability of the breath alcohol measurements questionable. According to various studies, the discrepancy between the operationally defined quantity and the concentration not related to the empirical interphase distribution coefficients, lays within (1-2) %, although there is also an evidence of a larger deviation. It is possible to construct a common metrological traceability chain by using reference gas mixtures in cylinders and dynamic gas mixture generators based on the principles not related to empirical equations, as well as determining more accurately the interphase distribution coefficient and evaluating its uncertainty. SE «Ukrmetrteststandart» possesses internationally recognised calibration and measurement capabilities for measuring ethanol concentration and producing reference materials: calibration gas mixtures of ethanol with nitrogen or air in cylinders and reference aqueous solutions of ethanol that provide metrological traceability for the breath alcohol measurements.

Marangoni condensation of steam-ethanol mixtures on a horizontal smooth tube

Experiments were conducted to measure condensation heat transfer of steam-ethanol mixtures on a horizontal smooth tube. Heat flux and vapor-to-surface temperature difference were accurately measured over a wide range of mass concentration of ethanol (0.001%, 0.005%, 0.01%, 0.025%, 0.05%, 0.1%, 0.5% and 1.0%.) at atmospheric pressure. The present work extends earlier data of Murase et al. (2007) and Ali et al. (2013) to lower mass concentration of ethanol and higher vapor-to-surface temperature difference. Visual observations, the appearance of condensate, show the condensation modes and their transitions of pseudo-dropwise, rivulets and filmwise. Heat flux and heat-transfer coefficient are found to increase, reach to a peak and decrease as vapor-to-surface temperature difference increases for all mass concentrations of ethanol and vapor velocities. The maximum heat-transfer coefficients appear in the range of mass concentration of ethanol from 0.01% to 0.025%. The highest heat-transfer coefficient values are 112.4 kW/m2 K and 93.9 kW/m2 K at ΔT = 3.43 K and 4.46 K, respectively. The maximum enhancement ratio of 5.5 is achieved at vapor-to-surface temperature difference of 4 K and mass concentration of ethanol 0.01%. The results also show that heat-transfer coefficient of filmwise eventually approaches to a value slightly higher than that of pure steam.

Ethanol production from cassava starch by protoplast fusants of Wickerhamomyces anomalus and Galactomyces candidum

ABSTRACT The potential of protoplast fusants of Wickerhamomyces anomalus and Galactomyces candidum isolates for ethanol production from cassava starch was evaluated. The protoplasts were obtained from 18 h yeast cells digested by zymolase and fused by polyethylene glycol (PEG). Regenerated recombinants were randomly selected and examined for desired marker traits: rate of fermentation of glucose, maltose and ethanol tolerance. Cassava starch hydrolysates were obtained by the amylolytic action of partially purified amylase extracts from Aspergillus species. Three of the selected fusants exhibited improvements in fermentation parameters over the parents. Enhanced ethanol tolerance of (25% v/v) as against 20% of the parents was exhibited by fusants R4 and R7. All isolates displayed higher ethanol productivity than CO2. The highest values of carbon dioxide productivity (4.79 L/L.h), volumetric ethanol productivity (11.54 g/L.h) and an ethanol mass concentration of 110.88 g/l were obtained from the fermentation by R1. Fusant R1 also had the highest fermentation efficiency (80%) and actual ethanol recovery (10.19%), as compared to other fusants and the parent yeast isolates. Parent isolates and selected fusants were characterized using molecular tools. The possibility of the occurrence of a genetic recombination in selected fusants as a result of protoplast fusion was observed.

Heat transfer during pseudo-dropwise condensation of water-ethanol vapor mixture on horizontal finned tubes

In the present work experimental data on heat transfer are obtained for the condensation of almost immobile pure steam and water-ethanol vapor mixture on three copper horizontal finned tubes with a cooled length of 100 mm. The fins are rectangular in shape, their height and thickness are 1 mm, and the spacing between fins 1.3, 2.0 and 3.0 mm. The experiments were carried out at pressures of 0.12…0.15 MPa, the vapor-to-surface temperature difference varied from 5 to 35 K. The mass concentration of ethanol in the vapor phase varied from 8.7 to 14.5%. The experimental data are presented in the form of the dependences of heat transfer coefficient on the vapor-to-wall temperature difference. The heat transfer coefficients for the condensation of pure steam are in good agreement with the calculations by the method of Srinivasan et al. According to experimental data for the condensation of the vapor mixture, diffusion thermal resistance and thermal resistance of the liquid phase at various ethanol concentrations and the spacing between fins were calculated.

Measurement of uncertainty for blood alcohol concentration by headspace gas chromatography

ABSTRACTMeasurement of uncertainty has recently become more relevant to the science of forensic toxicology for a variety of reasons. From accreditation to court testimony, measurement of uncertainty is being requested to accompany case results. The Toxicology Bureau of the New Mexico Department of Health has conducted a study to estimate a reasonable uncertainty for the mass concentration of ethanol, methanol, acetone, and isopropanol (g/100 mL) determined through dual capillary column headspace gas chromatography. In this measurement of uncertainty for BAC, alcohol encompasses ethanol, methanol, acetone, and isopropanol, and all four analytes are included in the final expanded uncertainty. One expanded uncertainty value incorporates all four analytes, simplifies the calculation, and streamlines the reporting process of the estimation of error. Three major groups were used in the estimation of the blood alcohol concentration expanded uncertainty: GC calibration adjustment slope, GC analytical, and certified reference material. The proportional standard uncertainties for these sources were combined using root-sum-squares to yield a combined standard uncertainty of uc = ±2.39% for the blood alcohol concentration method. The combined standard uncertainty was expanded to a confidence level of 95% with a coverage factor of 2. The final expanded uncertainty for the blood alcohol concentration method was U = ±4.8%.

Experimental study on flow condensation of mixture in a hydrophobic microchannel

The condensation flow patterns of ethanol–water mixture in a wide range of ethanol mass concentration inside a hydrophobic microchannel is experimentally studied via a high speed imaging system. The effects of channel surface wettability and ethanol concentration on flow condensation are compared and discussed. The experimental results indicate that the surface hydrophobic modification and ethanol concentration play a significant role in the flow condensation of mixture in a microchannel. The droplet condensation appears almost the whole two-phase flow region when the water steam is the main component, in which the droplet flow, droplet-streak flow, droplet-annular flow, droplet-injection flow and droplet-slug/bubble flow occur sequentially in a hydrophobic microchannel. With increasing ethanol concentration, the droplet-slug/bubble flow after droplet-injection flow disappears and is replaced by the pure slug/bubble flow. When the ethanol vapor is the main component, the droplet condensation almost disappears, and the annular-streak flow, annular flow, injection flow and slug/bubble flow appear sequentially along the flow direction. Both an increase in vapor Reynolds number and a decrease in ethanol concentration cause the injection location move toward the channel outlet. In addition, the surface hydrophobic modification introduces the droplet condensation, which is beneficial for the flow condensation heat transfer.

Measurement of Uncertainty for Aqueous Ethanol Wet-Bath Simulator Solutions Used with Evidential Breath Testing Instruments.

Aqueous ethanol wet-bath simulator solutions are used to perform calibration adjustments, calibration checks, proficiency testing, and inspection of breath alcohol instruments. The Toxicology Bureau of the New Mexico Department of Health has conducted a study to estimate a measurement of uncertainty for the preparation and testing of these wet-bath simulator solutions. The measurand is identified as the mass concentration of ethanol (g/100 mL) determined through dual capillary column headspace gas chromatography with flame ionization detector analysis. Three groups were used in the estimation of the aqueous ethanol wet-bath simulator solutions uncertainty: GC calibration adjustment, GC analytical, and certified reference material. The standard uncertainties for these uncertainty sources were combined using the method of root-sum-squares to give uc = 0.8598%. The combined standard uncertainty was expanded to U = 1.7% to reflect a confidence level of 95% using a coverage factor of 2. This estimation applies to all aqueous ethanol wet-bath simulator solution concentrations produced by this laboratory.

Visualization study of condensation of ethanol–water mixtures in trapezoidal microchannels

A visualization experiment is carried out to investigate the ethanol–water vapor mixtures condensation flow patterns in an array of microchannels under a wide range of concentration (2–60%). The text microchannel is a trapezoidal silicon channel with a hydraulic diameter of 165.87μm and a length of 50mm. Along the flow direction, annular, annular-streak, annular-streak-droplet, churn, injection, droplet-injection and bubble flow patterns are observed in the vapor mixtures condensation under different inlet ethanol mass concentration (60%, 31%, 20%, 6%, 4% and 2%), which is obviously different from pure steam condensation. The equivalent surface free energy differences under various vapor conditions and vapor–surface temperature differences are calculated quantitatively. The experimental results show that flow patterns are closely related to the equivalent surface free energy differences. A correlation based on the critical quality is proposed to indicate the injection two-phase flow patterns transition.

Modelling of surface plasmon resonance sensor for detection of mass concentration of ethanol and methanol in a binary mixture

Modelling of a surface plasmon resonance sensor for detection of ethanol or methanol content in water is presented. The reflectivities of these sensors are derived using transfer matrix method and hence the corresponding sensitivity and detection accuracy are obtained in the presence of high index overlayer, like silicon and chalcogenide. It is observed that the resonant wavelength of surface plasmon resonance sensor is shifted toward higher wavelength with increase of refractive index and thickness of overlayer. Hence, by adjusting their values, the desired spectral operation range of this sensor is obtained. The sensitivity of this sensor with silicon overlayer is larger than the chalcogenide overlayer but at the same time detection accuracy is smaller. This sensor can be used to detect the mass concentration of ethanol, methanol and other similar materials. A method to obtain the percentage mass concentration of ethanol is discussed.

Preparation, Properties of Partially Hydrolized Guar Gum

Guar gum is a highly viscous water soluble heteropolysaccharide obtained from guar seed endosperm portion. Partially hydrolyzed guar gum (PHGG) is low in viscosity and has the healthy benefits as the dietary fiber. In this study, the effect of amount of acidolysis agent, ethanol content, acidolysis temperature and time on the acidolysis degree of guar gum was investigated by using the solvent method. The thermal properties were characterized by the idifferential scanning calorimeter and thermogravimetric analyzer, respectively. It was showed that the better conditions for preparing PHGG were: acidolysis temperature 40°C, acidolysis time 4h, ethanol mass concentration 61%, respectively. The freeze-thaw stability, expansion capability decreased after guar gum was partially hydrolized by hydrochloric acid. The onset temperature, end temperature and peak temperature of PHGG all increased, but its melting enthalpy and thermal stability were reduced, compared with those of guar gum.

Study on Microwave - Assisted Extraction of the Yellow Pigment from Orange Peel

The article is about extracting the yellow pigment from orange peel with the aid of microwave.It mainly studies the effect of concentration of ethanol,the ratio of material and solution,microwave time,microwave power on the extraction percent of yellow pigment .The Orthogonal experiment shows that the order of factors which influence the extraction rate are microwave time,microwave power and mass concentration of ethanol. The optimized process conditions are mass concentration of ethanol as 85%,the ratio of material and solution as 1:16g/mL,microwave time as 8 minutes,microwave power as 200W,the extraction percent of yellow pigment can be 8.59%.

Ethanol fermentation from food processing waste

This study focuses on the use of restaurant waste for production of ethanol. Food wastes (corn, potatoes, and pasta) were converted to ethanol in a two‐step process: a two‐part enzymatic digestion of starch using α‐amylase and glucoamylase and then fermentation of the resulting sugars to ethanol using yeast. Because of the low initial composition of starch in the food waste, low ethanol concentrations were achieved: at best 8 mg/mL ethanol (0.8% by mass). Ethanol concentration increased with increasing enzyme dosage levels. Calculations were conducted to evaluate whether waste heat from restaurant waste could be used to drive flash vaporization to purify ethanol. If the solution produced by fermenting food waste is flashed at a temperature of 99.7°C, 77% of the ethanol is recovered in a vapor stream with 1.14 mol % ethanol (2.87 mass %). Waste heat could provide over a third of the energy for this vaporization process. If 4 mol % ethanol could be produced in the fermentation step by increasing the initial starch content in the waste solution and improving the fermentation process, then a single flash at 98.9°C will recover nearly 99% of the ethanol, giving a mass concentration of ethanol of 10.3%, which is similar to that achieved in industrial grain fermentation. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 1280–1283, 2013

Research on Dropwise Condensation for Binary Mixed Vapor

An experiment for Marangoni condensation of ethanol-water mixtures was carried out and the departing radius and drop size distribution on vertical surface was presented. An amended formula was obtained after considering the effect of ethanol mass concentration, vapor velocity and condensing temperature difference based on Le Fevre’s formula concerning departing radius of pure water, The calculations were in good agreement with experimental result, had a maximum error less than 23%. Owing to the significant effect on drop size contribution, vapor velocity was introduced into Rose’s formula, and the correctional result compared well with the experimental data.

Optimization, Kinetics, and Thermodynamics in the Extraction Process of Puerarin by Decompressing Inner Ebullition

Decompressing inner ebullition (DIE) is a novel method and it can achieve a rapid extraction at lower temperature for active constituents of medical plants. In this work, DIE was employed to extract puerarin from puerarin lobata (Willd.) Ohwi (PLO). The extraction conditions were investigated according single factor analysis. Experiment results showed that the extraction yield of puerarin reached a maximum value when the ethanol mass concentration in the aqueous solution immersing the PLO was 60%, the amount of ethanol solution for premaceration and of water for extraction were 1.6 and 10 mL·g–1 of PLO, respectively, the operation gauge pressure was −0.084 MPa, and the extraction temperature was 50 °C. Under the optimal conditions, the extraction kinetics of DIE was studied. The mass transfer coefficient of DIE ranged between 0.09 and 0.13 s–1, which is 183 times greater than that of ultrasonic assistant extraction under the same conditions, and its extraction activation energy ΔE is 10.86 kJ·mol–1. Also, the thermodynamics properties in the extraction process of DIE at 50 °C were also calculated, the enthalpy change ΔH is 58.76 kJ·mol–1, the entropy change ΔS is 224.50 J·mol–1·K–1, and Gibbs free energy ΔG is −13.73 kJ·mol–1, respectively. The extraction of DIE belongs to a spontaneous process with endothermic and entropy increasing.

Ethanol/water solutions as certified reference materials for breath alcohol analyzer calibration

The Federal Institute for Materials Research and Testing (BAM), Germany, has issued a series of large volume ethanol in water certified reference materials (CRMs), primarily developed for the calibration of evidential breath alcohol analyzers in Germany. The certified parameter is the ethanol mass concentration at 20 °C. When used in a wet bath simulator, the solutions deliver gas samples that meet the requirements set by the Organization of Legal Metrology for calibration of breathalyzers. The materials were prepared gravimetrically by spiking of ethanol into water in single 5 L units. A complete uncertainty budget for the preparation process has been established. The purity of the commercial ethanol stock solution was identified to be the main source of uncertainty. For stability and homogeneity measurements and for the verification of the gravimetric mass concentration of the CRMs, a robust high-precision gas chromatography, with flame-ionization detection method for ethanol determination in aqueous samples was developed and validated. The good performance of this method has been demonstrated in several international comparisons organized by the Consultative Committee for Amount of Substance—Metrology in Chemistry at the International Bureau of Weights and Measures.

Modelling of batch kefir fermentation kinetics for ethanol production by mixed natural microflora

Non-structured kinetic models are proposed for the mathematical description of principal kinetics involved in ethanol production during kefir fermentation in a batch reactor system. Experimental data collected from a series of batch fermentations, which were performed at constant temperature ( ϑ = 21 °C) and initial kefir grains mass concentration ( γ KG,0 = 42 g L −1) over different fermentation periods in the interval from (0–89) h, were used to estimate parameters and also to validate the proposed models. The optimal values of the kinetic parameters were approximated by minimizing the discrepancy between the model predictions and corresponding experimental data. The growth of kefir grains could be expressed by a logistic function model, which describes the growth as a function of initial kefir grains concentration, time, specific growth rate, and final kefir grains concentration. The modified Gompertz model, which gives the lag time, the specific production rate and the maximum ethanol mass concentration, was able to describe the formation of ethanol as the fermentation proceeded. In both cases, the model simulation matches well with the experimental observations, which made it possible to elucidate the fermentation characteristics of kefir grains during efficient ethanol production. These models thus can be employed for the development and optimization of bio-based ethanol production processes.

Density and Viscosity of Saturated Solutions of Lithium Potassium Sulfate + Water + Ethanol at 298.15 K

The solubility of lithium potassium sulfate double salt in water and in aqueous ethanol has been determined at a temperature of 298.15 K, in the ethanol mass concentration range of 0-0.4 kg of ethanol/kg of water. An equation is given for the solubility as a function of the composition of potassium sulfate in solution. The densities and viscosities of the saturated solutions are also reported. Equations are given for both properties as a function of the solubility.