Digital density meter

With this relationship for all samples was calculated from ninh This M is used for evaluating the reaction data. The ultracen rifuge (u.c measurements were carried out in a Spinco model E analytical ultracentrifuge, with 0.4% solutions in 90% formic acid containing 2.3 M KCl. By means of the sedimenta- ion diffusion equilibrium method of Scholte (13) we determine M, M and M. The buoyancy factor (1- vd = -0.086) necessary for tSe calculation of these molecular weights from ultracentrifugation data was measured by means of a PEER DMA/50 digital density meter. 

Density (the mass of liquid per unit volume at 15°C) and the related terms specific gravity (the ratio of the mass of a given volume of liquid at 15°C to the mass of an equal volume of pure water at the same temperature) and relative density (same as specific gravity) are important properties of petroleum products as they are a part of product sales specifications, although playing only a minor role in studies of product composition. Usually, a hydrometer, pycnometer, or digital density meter is used for determination in all these standards. 

The use of a precision digital density meter as supplied by Mettler Instruments (Anton Paar, Ag.) appeared attractive. Few references on using density measurements to follow polymerization or other reactions appear in the literature. Poehlein and Dougherty (2) mentioned, without elaboration, the occasional use of y-ray density meters to measure conversion for control purposes in continuous emulsion polymerization. Braun and Disselhoff (3) utilized an instrument by Anton Paar, Ag. but only in a very limited fashion. More recently Rentsch and Schultz(4) also utilized an instrument by Anton Paar, Ag. for the continuous density measurement of the cationic polymerization of 1,3,6,9-tetraoxacycloundecane. Ray(5) has used a newer model Paar digital density meter to monitor emulsion polymerization in a continuous stirred tank reactor train. Trathnigg(6, 7) quite recently considered the solution polymerization of styrene in tetrahydrofuran and discusses the effect of mixing on the reliability of the conversion data calculated. Two other references by Russian authors(8,9) are known citing kinetic measurements by the density method but their procedures do not fulfill the above stated requirements. 

Partial specific volumes were calculated from density measurements on poloxamer solutions made using a digital density meter (Paar DMA 02C). 

Density (ASTM D-1298, IP 160) is an important property of petroleum products because petroleum and especially petroleum products are usually bought and sold on that basis or, if on a volume basis, then converted to mass basis via density measurements. This property is almost synonymously termed as density, relative density, gravity, and specific gravity, all terms related to each other. Usually a hydrometer, pycnometer, or more modem digital density meter is used for the determination of density or specific gravity (ASTM 2000 Speight, 2001). 

Elemental Analysis and Physical Properties. Elemental analysis was accomplished by conventional microanalytical techniques in a commercial testing laboratory. Densities were measured on a Mettler/Paar digital density meter, model D.M. 40. Number average molecular weights were determined by VPO in benzene. Simulated distillation was accomplished using a 1/4" by 18" column of 3% dexsil 300 on chromosorb W, programmed from -30° to 350°C at 10°/minute with a 4 minute hold at 350°C. The detector was a flame ionization detector maintained at 400°C. 

For solution scattering, solvent densities can be calculated from standard tables of buffer densities and compositions. This procedure will allow for the non-ideality of concentrated buffer solutions that are used in some X-ray scattering studies (Table 2). Macromolecular partial specific volumes v can be experimentally determined by densitometry, usually with a Paar digital density meter, to measure the density of the buffer p uff the solutions p ,p over a concentration range ... 

Digital density meter was designed to measure relative density of petroleum distillates and viscous oils which are not volatile at temperatures from 15 to 35°C (vapor pressure below 600 mm Hg and viscosity below 15,000 cSt at measurement temperature). 

ASTM D4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter... 

Paucidisperse acetylated methylated and underivatized kraft lignin fractions were selected for absolute molecular weight determinations at 8 x lO g/liter concentrations in DMF and aqueous O.lOMNaOH, respectively, using the Beckman Optima XL-A analytical ultracentrifuge. The partial specific volumes of the solute species (0.744 cm Vg), and densities p of solvent or solution were measured with a Paar 60/602 digital density meter. The sedimentation curves were scaimed at two wavelengths (280 and 320 nm) after equilibrium had been reached at more than one suitable rotor speed the effective baseline at 600 nm was subtracted from each set of sedimentation equilibrium data to correct for... 

Several methods are used to determine speeifie gravity of the solvents, sueh as hydrometer, digital density meter, displaeemerrt, arrd pycnometer methods. 

The sulfonate concentration in the microemulsion was determined from the equilibrated microemulsion phase volume and the known weight of sulfonate in the system the assumption that the microemulsion phase contained all of the sulfonate was justified for all microemulsions. The volume fractions of oil and brine in the microemulsion were determined from the excess volumes of oil and brine, respectively. The microemulsion density and index of refraction needed to calculate the specific refraction (Eq. (1)) were measured on a Mettler-Paar DMA 40 digital density meter with accuracy of 0.0001 g/cm and a Zeiss Abbe refractometer ( 0.0001), respectively the temperature was controlled with an Exacal 100 and Endocal 150 constant temperature circulator-baths connected in series. Interfacial tensions between the microemulsion and equilibrated excess phases were measured on a University of Texas Spinning Drop Tensiometer or a Spinning Drop Tensiometer from S S Instrument Mfg. measurements were carried out until equilibrium values were obtained as indicated by constant readings over a period of at least 1 hour. 

Determine the density of the oil sample at the temperature of the receiver by means of a hydrometer by Praaice D 1298, by means of a digital density meter by Test Method D4052, and by using either the mathematical subroutines or tables of Guide D 1250, or a combination thereof. 

Note 1—If it is necessary to convert a result obtained using the digital density meter to a density at another temperature, the Petroleum Measurement Tables can be used only if the glass expansion factor has been excluded. 

D 3606 Test Method for Benzene and Toluene in Finished Motor and Aviation Gasoline by Gas Chromatography D40S2 Test Method for Density and Relative Density of Liquids by Digital Density Meter ... 

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