Chemical stability, mass loss and hydrolysis mechanism of sterile and non-sterile lipid-core nanocapsules: The influence of the molar mass of the polymer wall

2018 ◽  
Vol 133 ◽  
pp. 161-172 ◽  
Author(s):  
Selma Calgaroto ◽  
Lucas E. Fauri ◽  
Luiza A. Frank ◽  
Karina Paese ◽  
Sílvia S. Guterres ◽  
...  
Keyword(s):  
Mass Loss ◽  
Chemical Stability ◽  
Molar Mass ◽  
Hydrolysis Mechanism ◽  
Lipid Core ◽  
Polymer Wall

scholarly journals The influence of migration processes in gunpowder charge on the quality of mortar ammunition

2017 ◽  
Vol 71 (3) ◽  
pp. 231-240 ◽  
Author(s):  
Nikola Bobic ◽  
Radovan Simonovic ◽  
Sasa Drmanic ◽  
Stefan Milic ◽  
Jasmina Nikolic ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Mass Loss ◽  
Chemical Stability ◽  
Efficient Production ◽  
Gunpowder Charge

The study describes the results of static, physicochemical and ballistic examination of double-based gunpowder charges, in order to establish the deviations from the demanded quality of mortar ammunition. The examinations were carried out on gunpowder samples used for laboration of mortar shells 60, 82 and 120 mm caliber and consisted of periodical measurements of the gunpowder mass loss, basic ballistic parameters, and compatibility testing of gunpowder and celluloid containers as well as chemical stability determination. The estimation of the gunpowder quality was performed by comparative analysis and the suggestions for more efficient production of it were given.

scholarly journals Thermal Stabilization of Polyoxymethylene by PEG-Functionalized Hydroxyapatite: Examining the Effects of Reduced Formaldehyde Release and Enhanced Bioactivity

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Klaudia Król-Morkisz ◽  
Ewelina Karaś ◽  
Tomasz M. Majka ◽  
Krzysztof Pielichowski ◽  
Kinga Pielichowska
Keyword(s):  
Chemical Stability ◽  
Molar Mass ◽  
Thermal Stabilization ◽  
Melt Processing ◽  
Degree Of Crystallinity ◽  
Average Molar Mass ◽  
Thermal Stabilizer ◽  
Formaldehyde Release ◽  
Poly Ethylene

Nanostructured hydroxyapatite (HA) functionalized with poly(ethylene glycol) (HA-g-PEG) of different molar mass was used as a thermal stabilizer to prepare polyoxymethylene (POM) composites by a melt processing method. The chemical and crystalline structure of (HA-g-PEG) and POM/HA-g-PEG composites was investigated by means of FTIR and XRD. The thermal properties, degree of crystallinity, and melting behaviour of POM-based composites were analysed with TG, DSC, and TOPEM DSC methods. The tensile strength, Young’s modulus, toughness, and wettability of POM were investigated as well. A preliminary assessment of bioactivity, in vitro chemical stability, and formaldehyde release from POM/HA-g-PEG composites by Schiff’s test was also performed. An SEM/EDX method was used to observe the morphology of POM/HA-g-PEG composites. The results indicate that the addition of 1% HA-g-PEG slightly increases the melting temperature and degree of crystallinity. In small amounts, HA-g-PEG particles probably act as nucleating agents for the POM crystallization process. Incorporation of 5% HA-g-PEG to POM caused a decrease in the crystallinity of the polymer matrix, as a result, some mechanical properties of POM/HA-g-PEG composites also decreased. The thermal stability of POM/HA-g-PEG composites improved significantly from 309°C for unmodified POM to 342°C for POM/10.0% HA-g-PEG 600. The most effective thermal stabilizer was synthesized with the lowest mass-average molar mass PEG. The in vitro bioactivity test confirmed that, as the average molar mass of PEG in HA-g-PEG hybrids increased, POM-based composites indicated higher bioactivity. The in vitro chemical stability analysis results showed that both the POM matrix and the HA-g-PEG additive remain stable during the whole incubation time. Importantly, after seven days of dynamic incubation, no formaldehyde was detected in all filtrates, which is crucial in biomedical applications, among others.

scholarly journals Data of characterization and related assays of lipid-core nanocapsule formulations and their hydrolysis mechanism

Data in Brief ◽  
2018 ◽  
Vol 21 ◽  
pp. 918-933 ◽  
Author(s):  
Selma Calgaroto ◽  
Lucas E. Fauri ◽  
Luiza A. Frank ◽  
Karina Paese ◽  
Sílvia S. Guterres ◽  
...  
Keyword(s):  
Hydrolysis Mechanism ◽  
Lipid Core

Water accumulation as a function of temperature on specimens in an electron microscope cold stage

1986 ◽  
Vol 44 ◽  
pp. 114-115 ◽  
Author(s):  
M.K. Lamvik ◽  
D.A. Kopf ◽  
S.D. Davilla ◽  
J.D. Robertson
Keyword(s):  
Electron Microscope ◽  
Mass Loss ◽  
Liquid Helium ◽  
Liquid Nitrogen ◽  
Liquid Nitrogen Temperature ◽  
Liquid Helium Temperature ◽  
Helium Temperature ◽  
Cold Stage ◽  
Water Accumulation ◽  
Better Than

Last year we reported1 that there is a striking reduction in the rate of mass loss when a specimen is observed at liquid helium temperature. It is important to determine whether liquid helium temperature is significantly better than liquid nitrogen temperature. This requires a good understanding of mass loss effects in cold stages around 100K.

Electron Beam-Induced Mass Loss in Freeze-Dried Tissue and Protein Samples

1985 ◽  
Vol 43 ◽  
pp. 470-471
Author(s):  
M.E. Cantino ◽  
M.K. Goddard ◽  
L.E. Wilkinson ◽  
D.E. Johnson
Keyword(s):  
Electron Beam ◽  
Salivary Gland ◽  
Mass Loss ◽  
Counting Rate ◽  
Dose Dependence ◽  
X Ray ◽  
Large Samples ◽  
Freeze Dried ◽  
Muscle Homogenate ◽  
Large Muscle

Quantification in biological x-ray microanalysis depends on accurate evaluation of mass loss. Although several studies have addressed the problem of electron beam induced mass loss from organic samples (eg., 1,2). uncertainty persists as to the dose dependence, the extent of loss, the elemental constituents affected, and the variation in loss for different materials and tissues. in the work described here, we used x-ray counting rate changes to measure mass loss in albumin (used as a quantification standard), salivary gland, and muscle.In order to measure mass loss at low doses (10-4 coul/cm2 ) large samples were needed. While freeze-dried salivary gland sections of the required dimensions were available, muscle sections of this size were difficult to obtain. To simulate large muscle sections, frog or rat muscle homogenate was injected between formvar films which were then stretched over slot grids and freeze-dried. Albumin samples were prepared by a similar procedure. using a solution of bovine serum albumin in water. Samples were irradiated in the STEM mode of a JEOL 100C.

Elemental mass loss in silicate minerals during x-ray analysis

1990 ◽  
Vol 48 (4) ◽  
pp. 804-805
Author(s):  
P.E. Champness ◽  
R.W. Devenish
Keyword(s):  
Mass Loss ◽  
Current Density ◽  
Damage Mechanism ◽  
Beam Current ◽  
Single Chain ◽  
Plagioclase Feldspar ◽  
X Ray ◽  
Alkali Ions ◽  
Structural Order ◽  
Sheet Silicate

It has long been recognised that silicates can suffer extensive beam damage in electron-beam instruments. The predominant damage mechanism is radiolysis. For instance, damage in quartz, SiO2, results in loss of structural order without mass loss whereas feldspars (framework silicates containing Ca, Na, K) suffer loss of structural order with accompanying mass loss. In the latter case, the alkali ions, particularly Na, are found to migrate away from the area of the beam. The aim of the present study was to investigate the loss of various elements from the common silicate structures during electron irradiation at 100 kV over a range of current densities of 104 - 109 A m−2. (The current density is defined in terms of 50% of total current in the FWHM probe). The silicates so far ivestigated are:- olivine [(Mg, Fe)SiO4], a structure that has isolated Si-O tetrahedra, garnet [(Mg, Ca, Fe)3Al2Si3AO12 another silicate with isolated tetrahedra, pyroxene [-Ca(Mg, Fe)Si2O6 a single-chain silicate; mica [margarite, -Ca2Al4Si4Al4O2O(OH)4], a sheet silicate, and plagioclase feldspar [-NaCaAl3Si5O16]. Ion- thinned samples of each mineral were examined in a VG Microscopes UHV HB501 field- emission STEM. The beam current used was typically - 0.5 nA and the current density was varied by defocussing the electron probe. Energy-dispersive X-ray spectra were collected every 10 seconds for a total of 200 seconds using a Link Systems windowless detector. The thickness of the samples in the area of analysis was normally 50-150 nm.

Paper Chemistry: Interactions of thermo mechanical pulp fractions with high molar mass cationic polyacrylamides: Part 2. Flocculation

2010 ◽  
Vol 25 (3) ◽  
pp. 310-318 ◽  
Author(s):  
Tero Taipale ◽  
Janne Laine ◽  
Susanna Holappa ◽  
Jonni Ahlgren ◽  
Juan Cecchini
Keyword(s):  
Molar Mass ◽  
High Molar Mass ◽  
Mechanical Pulp ◽  
Paper Chemistry
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