Application of Gas Pycnometry for the Density Measurement of Freeze-Dried Products

Stange, Ulrike; Scherf-Clavel, Maike; Gieseler, Henning

doi:10.1002/jps.23723

Cited by 21 publications

(10 citation statements)

References 44 publications

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“…Another very important aspect of the sample volume is that the measured sample density is dependent on the sample volume. Multiple studies [6,7,11] show that with decreasing filling ratio the measured sample density decreases. This trend is shown exemplary in Figure 1 for the measurement of glass beads carried out by micromeritics [11].…”

Section: Sample Volumementioning

confidence: 99%

“…With the exception of the calibration standards, all measured samples discussed in this paper exhibited a decrease in measured density over the course of 10 to 400 data points. And while it appears obvious that evaporating water could not be responsible, because water evaporation should decrease the sample volume and, therefore, increase the density over time, the opposite is the case [6,7,9,[13][14][15]. As the pressurised helium is virtually free of water the partial pressure of water is also zero.…”

Section: Sample Drynessmentioning

confidence: 99%

“…Viana et al [6] have published what is probably the most in-depth analysis of the influences on and optimal conditions for pycnometric density determination. Since then, some studies have used ANOVA [7] or confidence intervals [3] to analyse their results, but no fundamental analysis of the statistical character of the pycnometric measurement and the impact of the varying influences on the measurement have been published. So, to this date it is unexplored what the true accuracy of a pycnometric measurement is and whether the nature of the obtained data points even allows for the use of statistical tests.…”

Section: Introductionmentioning

confidence: 99%

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High‐Precision Density Measurements of Energetic Materials for Quality Assessment

Herrmannsdörfer

Klapötke

2021

Propellants Explo Pyrotec

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Even though helium pycnometry is considered a very precise method of density determination, its use to analyse factors influencing crystal quality (e. g. solvent inclusions, amorphous states, crystal defects…) is limited due to the unknown inherent accuracy of the method. Previous studies have attempted to identify the best possible accuracy of helium pycnometry. However, no robust method has been proposed to validate even the precision obtained. This means that the often occurring, seemingly random density deviations have never been satisfactorily explained. In this study the influencing factors on density measurements of the CL‐20/HMX cocrystal and phase stabilised ammonium nitrate carried out with an AccuPyc 1340 TEC were quantified and a robust method of data analysis was developed to judge with certainty the quality and significance of the data obtained. This study shows that statistical tests such as the t‐test and ANOVA cannot be utilised to differentiate between samples or repeat measurements, even though the density data points exhibit a normal distribution. By utilising confidence intervals and quantifying the three major sources of error (sampling error, change in barometric pressure during the measurement, and weight in error), a repeatability of 0.015 % was achieved and a method was developed that enables differentiation between samples with a certainty as good as 0.05 %.

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Section: Sample Volumementioning

confidence: 99%

Section: Sample Drynessmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High‐Precision Density Measurements of Energetic Materials for Quality Assessment

Herrmannsdörfer

Klapötke

2021

Propellants Explo Pyrotec

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“…This value quantifies the absolute number of building units in a given amount of crystal volume, complementing the information regarding their relative amounts obtained from other characterization methods. For this purpose, the best available analyses are gas pycnometry, [44,45] mercury porosimetry, [46] and mass correlation spectroscopy. [47,48] So far, we have outlined a comprehensive albeit not necessarily complete list of analytical techniques and stressed the importance of their complementarity in gathering different types of information.…”

Section: Connection Completeness (κ) Describes the Degree Of Architecmentioning

confidence: 99%

Section: Aging Assessment: Experimental Tools For Analyzing Architectmentioning

confidence: 99%

Circumventing Wear and Tear of Adaptive Porous Materials

Canossa

Wuttke

2020

Adv Funct Materials

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The assessment of the architectural stability of molecular porous materials is not yet a common practice, but critical to their understanding and development. The conformational adaptation of porous materials to guest binding and other chemical dynamics poses a risk of architectural damage, leading to performance deterioration during their prolonged usage. The deformation of the framework backbone and the disconnection of building units are driven by chemical, mechanical, and thermal perturbations, and can be quantitatively described by the term connection completeness. Analytical means that can be used to measure this parameter are presented in order to provide a standard, practical protocol for evaluating architectural damage made to framework materials. Preventive and remedial strategies are proposed for enhancing the architectural integrity of frameworks without compromising their functional mechanisms, paving the way to the design of robust yet adaptive materials. In this way, the discussion on architectural stability is initiated, and readers are encouraged to carefully characterize molecular porous materials for a better understanding of their structure-property relationship.

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Food Powders Particle Properties

Baysan

Koç

2020

Food Engineering Series

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Application of Gas Pycnometry for the Density Measurement of Freeze-Dried Products

Cited by 21 publications

References 44 publications

High‐Precision Density Measurements of Energetic Materials for Quality Assessment

High‐Precision Density Measurements of Energetic Materials for Quality Assessment

Circumventing Wear and Tear of Adaptive Porous Materials

Food Powders Particle Properties

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