Introduction

Dymond, J. H.; Marsh, Kenneth N.; Wilhoit, R. C.; Wong, K. C.

doi:10.1007/10693952_2

Cited by 27 publications

(61 citation statements)

References 36 publications

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“…If we assumed that all the water was vaporized and hence created pores inside the specimen, we could calculate the corresponding vapor volume from mass conservation. Similar to other gases, water vapor is not an ideal gas, and corrections need to be applied to the ideal gas law, as done here with Equation (3) [ 35 ]:

where P is the pressure inside the nozzle; ρ is the molar density, which is correlated with both vapor mass and volume; R is the gas constant of 8.314 J/(K·mol); and T is the material temperature, which in principle shall be equal to the nozzle temperature of 280 °C (553 K) but in practice it could be lower considering thermal conduction takes time [ 36 ]. From our IR observations, the material temperature could have been 15 °C lower than nozzle temperature after coming out of the nozzle.…”

Section: Resultsmentioning

confidence: 99%

Effects of Environmental Temperature and Humidity on the Geometry and Strength of Polycarbonate Specimens Prepared by Fused Filament Fabrication

et al. 2020

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It is widely known that the printing quality of fused filament fabrication (FFF) is heavily affected by environmental temperature and humidity, taking the form of warping and porosity. However, there is little understanding about the quantitative relations between environmental conditions, geometry, and the mechanical properties of printed parts. In this study, we systematically investigated those relations using bisphenol A polycarbonate as a model material system. For the environmental temperature, an in-situ infrared imaging analysis revealed the presence of an up to 5.4 °C/mm thermal gradient when printing using an open-chamber printer and a heated build plate. For the environmental humidity, an analysis of X-ray micro-computed tomography (micro-CT) scans showed an up to 11.7% porosity that was brought by polymer water content absorbed from environmental moisture. Meanwhile, tensile tests showed a mechanical performance loss associated with those defects, but, surprisingly, the transverse direction ductility had the potential to increase at a higher porosity. Furthermore, the experimental results were combined with analytical and parametrical studies to elucidate quantitative relations between environmental conditions and printing quality. Based on the results, quantitative guidelines for the estimation of printing quality based on environmental conditions are provided that would also help users to obtain desired printing results with a better understanding of the effects of environmental conditions.

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Section: Resultsmentioning

confidence: 99%

Effects of Environmental Temperature and Humidity on the Geometry and Strength of Polycarbonate Specimens Prepared by Fused Filament Fabrication

et al. 2020

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“…The second virial coefficient B was calculated using equations I or II for any given temperature. The data was taken from a comprehensive reference book [ 102 ], which covers second virial coefficients for more than 250 compounds. Given the temperature dependence, the overall number of data points is more than 4500.…”

Section: Qspr Models Based On Simplex Descriptorsmentioning

confidence: 99%

“…To our knowledge, [ 78 ] is the first attempt at a QSPR model for this coefficient. Dymond et al [ 102 ] compilation was the source of the data for the 126 mixtures and 1211 values (each mixture selected had at least 4 values) of B 12 at different temperatures ranging from 200-600 K. The test set comprised of compounds with less than 4 data values for a total of 102 mixtures and 188 data points at different temperatures. Given the sole focus of B 12 on the heterogenous mixture values, the SiRMS descriptors for individual components were removed from the model.…”

Section: Qspr Models Based On Simplex Descriptorsmentioning

confidence: 99%

Simplex representation of molecular structure as universal QSAR/QSPR tool

et al. 2021

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We review the development and application of the Simplex approach for the solution of various QSAR/QSPR problems. The general concept of the simplex method and its varieties are described. The advantages of utilizing this methodology, especially for the interpretation of QSAR/QSPR models, are presented in comparison to other fragmentary methods of molecular structure representation. The utility of SiRMS is demonstrated not only in the standard QSAR/QSPR applications, but also for mixtures, polymers, materials, and other complex systems. In addition to many different types of biological activity (antiviral, antimicrobial, antitumor, psychotropic, analgesic, etc.), toxicity and bioavailability, the review examines the simulation of important properties, such as water solubility, lipophilicity, as well as luminescence, and thermodynamic properties (melting and boiling temperatures, critical parameters, etc.). This review focuses on the stereochemical description of molecules within the simplex approach and details the possibilities of universal molecular stereo-analysis and stereochemical configuration description, along with stereo-isomerization mechanism and molecular fragment “topography” identification.

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“… iii See Appendix A for a discussion on B ρ ; C ρ is based on a fit to the data of Dymond et al 15 over temperatures close to our range of interest. The value in the table is calculated at 302.919 K from: C ρ ( T ) = 1432 + 2.923 · ( T − 300) − 0.781 · ( T − 300) 2 .…”

Section: Figmentioning

confidence: 99%

“…3(a), where we have selected values from Dymond et al 15 in the range (290 < T < 310) K, which have stated uncertainties of 0.3 cm 3 /mol or less. (The uncertainties stated in Dymond et al are represented in Fig.…”

Section: Density Second Virial Bρmentioning

confidence: 99%

Comparison measurements of low-pressure between a laser refractometer and ultrasonic manometer

Egan

Stone

Ricker

et al. 2016

Review of Scientific Instruments

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We have developed a new low-pressure sensor which is based on the measurement of (nitrogen) gas refractivity inside a Fabry–Perot (FP) cavity. We compare pressure determinations via this laser refractometer to that of well-established ultrasonic manometers throughout the range 100 Pa to 180 000 Pa. The refractometer demonstrates 10−6 · p reproducibility for p > 100 Pa, and this precision outperforms a manometer. We also claim the refractometer has an expanded uncertainty of U(pFP) = [(2.0 mPa)2 + (8.8 × 10−6 · p)2]1/2, as realized through the properties of nitrogen gas; we argue that a transfer of the pascal to p < 1 kPa using a laser refractometer is more accurate than the current primary realization.

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Introduction

Cited by 27 publications

References 36 publications

Effects of Environmental Temperature and Humidity on the Geometry and Strength of Polycarbonate Specimens Prepared by Fused Filament Fabrication

Effects of Environmental Temperature and Humidity on the Geometry and Strength of Polycarbonate Specimens Prepared by Fused Filament Fabrication

Simplex representation of molecular structure as universal QSAR/QSPR tool

Comparison measurements of low-pressure between a laser refractometer and ultrasonic manometer

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