Pycnometer Method Research Articles

Measurement of the change in partial molar volume during electrode reaction by gravity electrode—II. Examination of the accuracy of the measurement

The reliability of the measurement of the change in partial molar volume between product and reactant ions measured by gravity electrode (GE) was examined by the thermodynamic measurement of pycnometer (PM). Since the PM method requires an experimental equation of the apparent molar volume to calculate the partial molar volumes of the individual ions, the most suitable experimental equation must be first determined. As a test reaction for the experiment, oxidation of ferrocyanide (FERO) ion to ferricyanide (FERI) ion was adopted. After fitting several experimental equations to the data of the apparent molar volumes by the PM method, the calculated changes in the partial molar volume were compared with the data of the GM method. Then, it is concluded that the polynomial with a degree of 3 of the logarithm of the molality of the FERO ion suggests the most suitable equation. As a result, the reliability of the GE method was also experimentally validated.

Influence of dilution on the thermophysical properties of Dax peloid (TERDAX®)

In thermotherapy, the efficiency of a peloid depends in particular on its thermal quality and an appropriate and detailed chemical and physical characterization is necessary to understand the thermal behaviour of these products. The most influential physical properties are the specific heat capacity, the thermal conductivity and the density. This work focuses on the study of the evolution of those properties of Dax peloid mixed with thermal and mineral water as a function of the mud concentration. The experimental specific heat capacity data were measured using a Calvet calorimeter, SETARAM BT 2.15, which permits studying with high precision all kind of substances and materials (oils, polymers, hydrates, powders) and simulate almost any process condition (reactions, crystallisation, freezing, etc.) and in the temperature range from 298.15 to 314.15K. The pycnometer method and an Anton-Paar DMA-4500 vibrating-tube densimeter were used to measure density values while the thermal conductivity was determined by the Model KD2 Pro, Decagon Devices Inc. The experimental data show the expected behaviour: the specific heat capacity increases with temperature and decreases with concentration whereas density decreases with temperature and increases with concentration. Besides the thermal conductivity increases with both temperature and concentration. The results of this study will be used to determine the best proportion between peloid and mineral water for an individual mud bath.

Density, partial molar volume, and excess volume of solutions of acrylic acid in acetonitrile, 1,2-dichloroethane, hexane, and benzene at 293 K

Using pycnometric method, we have measured density of the solutions of acrylic acid in acetonitrile, 1,2-dichloroethane, hexane, and benzene at 293 K and atmospheric pressure. The values of the excess molar volume for these systems and the values of the partial molar volumes of components were derived. In the whole concentration range the excess molar volume for binary mixtures of acrylic acid and either 1,2-dichloroethane, or benzene, or hexane has positive values, and in the system of acrylic acid-acetonitrile the value is negative.

Physical properties of acerola and blueberry pulps

In this work, some physical properties of acerola and blueberry pulps were determined. The density was determined by the pycnometer method; the electrical conductivity using a conductivimeter; the thermal diffusivity by a method based on the analytical solution of heat diffusion equation; the specific heat capacity by a modified method of mixtures; and the thermal conductivity from the knowledge of other properties. Results showed that the density of acerola pulp, in the temperature range between 303 and 353K, varies between 0.97 and 1.03kgm−3; for blueberry it ranged between 0.98 and 1.05kgm−3. Electrical conductivity was between 1.69 and 8.48mScm−1 for acerola pulp and between 0.79 and 3.86mScm−1 for blueberry. Specific heat, thermal diffusivity and thermal conductivity of acerola pulp at approximately 313K showed values of 4172.49Jkg−1K−1, 1.53×10−7m2s and 0.65Wm−1K−1, respectively. For blueberry, these values were 4050.39Jkg−1K−1, 1.51×10−7m2s and 0.64Wm−1K−1.

Porosity determination of deep‐fat‐fried coatings using pycnometer (Fried batter porosity determination by pycnometer)

SummaryThe effect of processing conditions such as frying time and temperature, and batter formulation on pore development in deep‐fat fried chicken nuggets coatings were studied using helium pycnometer method. Chicken nuggets with preformed and laboratory prepared batter coatings were fried at temperatures between 170 and 190 °C for a time range between 0 and 240 s. There was significant (P < 0.05) effect of frying temperature and batter formulation on porosity. Porosity increased with frying time and temperature, and ranged between 2.15 and 47.92% for the preformed batter and 9.96 and 54.76% for the formulated batters. Apparent and bulk densities of the preformed batters increased and decreased with frying time, respectively, but both declined gradually with increasing frying temperature. As the level of rice flour in the formulation increased, apparent and bulk densities also increased. Batter formulation and frying temperature significantly (P < 0.05) influenced the variation in moisture and fat content of the fried batter. Porosity demonstrated positive and negative correlation with fat uptake and moisture loss, respectively, for all the batter coatings.

Porosity and pore size distribution of different wood types as determined by mercury intrusion porosimetry

In this work, densities and porosity parameters are determined on domestic and overseas soft- and hardwoods by application of pycnometric methods and mercury intrusion porosimetry (MIP). Great variability was found in bulk density, porosity and in the specific surface area. According to the pore size distribution, four pore size classes could be distinguished: macropores (radius 58–2 μm and 2–0.5 μm), mesopores (500–80 nm), and micropores (80–1.8 nm). The pore size distribution can vary even in the case of comparable pore volumes. The hardwoods, particularly the European diffuse-porous ones, show a higher amount of micropores, which represent the microvoids or cell wall capillaries. A high cumulative pore volume can also be the result of a high content of micropores with poorer accessibility. The value of the total specific surface area from MIP measurements is, generally, below those values obtained by the water vapour adsorption technique. These results can provide information for further investigations on the sorption behaviour and the fluid intake as technological characteristics in industrial processes of impregnation and penetration of coating materials or adhesives.

Preparation of drop-deposited quantitative uranium sources with low self-absorption

Abstract A source preparation procedure was optimised for 235U sources of about 1 mg or 100 Bq, to be standardised for their activity concentrations by α-particle counting at a defined solid angle. The aim was to obtain quantitative sources having a thin, homogeneous active layer with low self-absorption of the emitted α-particles. The procedure involves spraying the wetting and seeding agent in a circular shape onto a glass or stainless steel substrate, quantitative drop deposition of active solution onto the sprayed area by the pycnometer method and fast drying of the source on a heating plate. The fraction of heavily scattered and self-absorbed α-particles could be reduced to 0.05–0.1% for a majority of the sources.

Evaluation of cure shrinkage measurement techniques for thermosetting resins

Resin chemical shrinkage dictates the surface integrity and the roughness of a composite structure. Thus, to minimize surface failures and to produce a good surface quality it is a requisite to be able to measure and track resin shrinkage during the cure process. This manuscript investigates and evaluates the measuring and monitoring of real-time resin shrinkage using a rheometer, a helium-based pycnometer and a thermo-mechanical analyzer (TMA) for ambient curing UP and epoxy resins. Shrinkage readings obtained from the newly developed robust technique with the rheometer concur well with readings from the traditional pycnometric method. They also coincide within the accepted literature values of 7–10% and 3.5–4.5% for the UP and epoxy systems, respectively. Shrinkage measurements during post-cure were effectively carried out at an elevated temperature, suggesting that the methodology provided can be applied to non-ambient curing systems. The TMA was found to be unsuccessful in measuring shrinkage reliably.

The density and molar volumes of ternary alloys of cross sections of the sodium-potassium-cesium system technically important temperatures

The density of well over 130 liquid ternary alloys of the Na-K-Cs system along the cross sections extending towards the vertexes of potassium, cesium, and sodium of the triangle of compositions is determined experimentally and by a numerical-and-graphic method. The pycnometric method is used for measuring the density in the temperature range from liquidus temperature to 553 K. The relative experimental error is 0.10% at confidence probability of 95%. The polytherms of density and molar volumes of the alloys are described by linear equations. In so doing, the isotherms of density of cesium-“rich” ternary alloys exhibit positive deviations, and the isotherms of molar volumes exhibit minor negative deviations from additivity, which are indicative of the nonideality of the solutions of the Na-K-Cs system.

Image vision technology for the characterisation of shape and geometrical properties of two varieties of lentil grown in Turkey

Geometrical features of lentil seeds (<I>Lens culinaris</I> Medik) were analysed using the image analysis LUCIA system Ver. 3.52. The values of the weight of 1000 kernels, kernel density, specific volume, specific surface area, and surface area of 1000 kernels of red and green lentils were determined as 66.61 and 138.56 g, 1504.5 and 1376.4 kg/m<sup>3</sup>, 0.6647 and 0.7265 cm<sup>3</sup>/g, 0.594 and 0.579 m<sup>2</sup>/kg, 395.4 and 801.9 cm<sup>2</sup>,, respectively. The lentil volume was simulated by an oblate spheroid and two sphere segments and the volumes obtained with both models were compared with that obtained by pycnometric method. Percentage differences of the two sphere segment approximation for red and green lentils were 4.4% and 4.2%, respectively. The height (thickness) of lentils was constant and practically the same with both varieties (2.6 mm) and therefore it was possible to simplify the geometrical models. Thus, 2D image analysis is suitable for a quick evaluation of the specific volume and surface area of grains on the basis of the projected area (equivalent diameter) without the measurement of the height. Image processing provides a simple, rapid, and non-invasive methodology to estimate lentil geometric features and engineering parameters.

Radio-frequency (RF) studies of the magneto-dielectric composites: Cr 0.75Fe 1.25O 3 (CRFO)–Fe 0.5Cu 0.75Ti 0.75O 3 (FCTO)

This paper concerns a study about the electrical properties of Cr 0.75Fe 1.25O 3 (CRFO)/Fe 0.5Cu 0.75Ti 0.75O 3 (FCTO) magneto-dielectric composites. These compounds were prepared by the conventional solid-state reaction synthesis. The samples synthesized, as well their two-phase composites [Cr 0.75Fe 1.25O 3] Z –[Fe 0.5Cu 0.75Ti 0.75O 3] 100− Z ( Z=17, 34, 50, 66, 83), were characterized by X-ray powder diffraction technique (XRD). Rietveld's method was employed to verify the quantitative phase abundances in the composites’ and their theoretical densities, which were compared with the experimental densities (pycnometer method). To predict the effect of the phases in the composites effective dielectric function ( κ), traditional dielectric mixing models such as parallel, series, and Lichtenecker's model were observed. An alternative approach, a sigmoidal fitting function based on the Boltzmann equation, was proposed to fit the experimental data.

Cortical Aerenchyma formation in hypocotyl and adventitious roots of Luffa cylindrica subjected to soil flooding.

Aerenchyma formation is thought to be one of the important morphological adaptations to hypoxic stress. Although sponge gourd is an annual vegetable upland crop, in response to flooding the hypocotyl and newly formed adventitious roots create aerenchyma that is neither schizogenous nor lysigenous, but is produced by radial elongation of cortical cells. The aim of this study is to characterize the morphological changes in flooded tissues and the pattern of cortical aerenchyma formation, and to analyse the relative amount of aerenchyma formed. Plants were harvested at 16 d after the flooding treatment was initiated. The root system was observed, and sections of fresh materials (hypocotyl, tap root and adventitious root) were viewed with a light or fluorescence microscope. Distributions of porosity along adventitious roots were estimated by a pycnometer method. Under flooded conditions, a considerable part of the root system consisted of new adventitious roots which soon emerged and grew quickly over the soil surface. The outer cortical cells of these roots and those of the hypocotyl elongated radially and contributed to the development of large intercellular spaces. The elongated cortical cells of adventitious roots were clearly T-shaped, and occurred regularly in mesh-like lacunate structures. In these positions, slits were formed in the epidermis. In the roots, the enlargement of the gas space system began close to the apex in the cortical cell layers immediately beneath the epidermis. The porosity along these roots was 11-45 %. In non-flooded plants, adventitious roots were not formed and no aerenchyma developed in the hypocotyl or tap root. Sponge gourd aerenchyma is produced by the unique radial elongation of cells that make the expansigeny. These morphological changes seem to enhance flooding tolerance by promoting tissue gas exchange, and sponge gourd might thereby adapt to flooding stress.

Preparation of radioactive sources for radionuclide metrology

The final accuracy of a radioactivity measurement can depend to a high degree on the quality of the radioactive sources used. In this paper the most important source preparation technique for radionuclide metrology is described in detail, namely the quantitative preparation of solid sources by drop deposition. Different steps in this source preparation procedure are described, such as preparation of source supports, preparation of dilutions, quantitative drop deposition by the pycnometer method, mass determination, control and improvement of the source quality and the uncertainty calculations involved. Other source preparation techniques of special interest are briefly mentioned and the handling and storage of solutions and sources are discussed.

Dimethacrylate based on cycloaliphatic epoxide for dental composite

Objectives The aim of this study was to investigate the kinetics and mechanical properties of dimethacrylate monomer based on cycloaliphatic epoxide for dental restorative composite. Methods Dimethacrylate based on cycloaliphatic epoxide (EPCDMA) was copolymeirzed with TEGDMA by varying the curing conditions: monomer composition and light intensity. A real-time near FTIR technique was employed to monitor the double bond conversion and the rate of polymerization. Dynamic mechanical analysis was performed on a dynamic mechanical analyzer, and volume shrinkage of the cured samples was determined by pycnometric method. Results The results of kinetics showed that, two peaks of maximum rate of polymerization ( R p max) occurred when the amount of TEGDMA was more than 30 wt%. Increasing the amount of TEGDMA, the final double bond conversion and polymerization shrinkage both increased, while the glass transition temperature ( T g) decreased. All EPCDMA/TEGDMA mixtures had slightly higher storage modulus at body temperature (37 °C). When compared with Bis-GMA/TEGDMA (70/30), the EPCDMA/TEGDMA (70/30) system assumed similar reactivity and volume shrinkage but higher T g. Significance EPCDMA had comparable mechanical properties to those of Bis-GMA.

Density of Ni-Co-Al Ternary Alloys in Liquid States Measured by a Modified Pycnometric Method

The density of Ni-Co-Al ternary alloys with a relative fixed mole ratio of Ni/Co(xNi:xCo≈86:14) and aluminum concentration change from 0 to 10% mass fraction in liquid states were measured by a modified pycnometric method(MPM). It was found that the density of the liquid Ni-Co-Al alloy decreases with increasing temperature, Al concentration and the ratio of Al concentration to Ni concentration in the alloy. The temperature coefficient of density changes with increasing the Al concentration or the ratio of Al concentration to Ni concentration in the ternary alloys. The measured densities by MPM were comparable with that by the modified sessile drop method, the maximum difference of density between them was about ±0.56%. The molar volume of liquid Ni-Co-Al alloy increases with increasing temperature and changed with increasing Al concentration. And the partial molar volume of aluminum in Ni-Co-Al alloy was calculated approximately. The molar volume of liquid Ni-Co-Al ternary alloy determined in the present work shows a negative deviation from the ideal linear molar volume.

Thermal synthesis and characterization of AlχLa1-χ P3O9

Abstract New binary lanthanum-aluminum triphosphates were synthesized by thermal-condensation method from H3PO4, La2O3 and Al(OH)3. These pigments could be potentially used as special inorganic pigments; their corrosion-inhibition properties were widely studied. Synthesis conditions were determined on the basis of DTA and TG measurements. The products were also characterized by X-ray diffraction analysis. Physical properties — density by pycnometric method, particle size distribution, oil number and critical pigment volume concentration (CPVC), pH and specific conductivity of their aqueous extracts were also determined.

Olmiite, CaMn[SiO3(OH)](OH), the Mn-dominant analogue of poldervaartite, a new mineral species from Kalahari manganese fields (Republic of South Africa)

Abstract Olmiite, ideally CaMn[SiO3(OH)](OH), is a newly identified mineral from the N’Chwaning II mine of the Kalahari manganese fields (Republic of South Africa), which occurs as a product of hydrothermal alteration associated with poldervaartite, celestine, sturmanite, bultfonteinite and hematite. The mineral occurs as wheat-sheaf aggregates consisting of pale to intense reddish pink minute crystals. Olmiite is transparent with vitreous lustre, and exhibits deep-red fluorescence under short-wave UV-light. The mineral is brittle, with irregular fracture. Streak is white and Mohs hardness is 5–51/2. No cleavage was observed. The measured density (pycnometer method) is 3.05(3) g/cm3. The calculated density is 3.102 g/cm3 or 3.109 g/cm3 using the unit-cell volume from single-crystal or powder data, respectively. Olmiite is biaxial positive, with refractive indices α = 1.663(1), β = 1.672(1), γ = 1.694(1) (589 nm), 2Vmeas = 71.8(1)º, 2Vcalc = 66(8)º. The optical orientation is X = a, Y = c, Z = b and dispersion: r > v, distinct. Pleochroism is not observed. Chemical analysis by electron microprobe yielded the chemical formula (Ca2–xMnxFey)[SiO3(OH)](OH), with 0.84 ≤ x ≤ 0.86, and y ≤ 0.01. Olmiite is orthorhombic, space group Pbca, with a = 9.249(3), b = 9.076(9), c = 10.342(9) Å , V = 868(1) Å 3 and Z = 8. The strongest five powder-diffraction lines [d in Å , (I/Io), hkl] are: 4.14, (45), 021; 3.19, (100), 122; 2.807, (35), 311; 2.545 (35), 312; 2.361, (40), 223. Single-crystal structure refinement (R1 = 2.74% for 1012 observed reflections) showed that the atomic arrangement of olmiite is similar to that of poldervaartite, with all Mnordered onthe M2 site. Significant variations in bond distances and angles are related to the pronounced difference in the Mn content. Olmiite, therefore, is the Mn-dominant analogue of poldervaartite. The name poldervaartite should be reserved for samples having Ca dominant at the M2 site.

Synthesis and properties of molybdenum tellurite glasses of the BaCl2-MoO3-TeO2 system

Molybdenum tellurite glasses of the BaCl2-MoO3-TeO2 system have been synthesized. The effect of barium chloride on the density and spectral properties of the glasses has been studied using the pycnometer method and IR spectroscopy, respectively.

PuAl alloys density measurements using gas pycnometer: First results

Plutonium alloys density is an important data to determine some metallurgical parameters like martensitic (α′) phase fraction (in relation with delta phase stability studies) and to quantify swelling (in relation with self radiation phenomena studies). Density is usually obtained by Archimedes technique. Density measurements on plutonium alloys using gas pycnometer have recently been developed in order to improve accuracy. This paper presents results for delta plutonium alloys (Pu 1.8–5.8 at% Al). The measurements by Archimedes technique and gas pycnometer give the same mean density but the accuracy is divided by 10 for the gas pycnometer method. The first results obtained with gas pycnometer are in agreement with literature.

Anomalous behavior of glycerol–water solutions

Measurements of density for glycerol–water solutions have been carried out along a co-existing curve by using the pycnometer method in the range of temperatures from 293 to 363 K and in the range of concentration from 0.225 to 0.552 mol fraction of glycerol. It's shown that the concentration curve of density is not monotone. The density of the glycerol–water solution is a jump function of concentration. The peak of this curve is observed at concentration of 0.33 mol fraction of glycerol. It is found that this concentration is characterized by the highest values of isobaric expansion. We also found that the investigated glycerol–water solutions are obtained with compression based on configurational rather than energetic principles.