Aging Study of a Paste Explosive Based on RDX/RTV (Cyclotrimethylenetrinitramine/Room Temperature Vulcanizing) Silicone Using Rheological Property

2021 ◽  
Vol 94 (9) ◽  
pp. 1267-1274
Author(s):  
Hamid Reza Pouretedal ◽  
Sajjad Damiri ◽  
Sheida Nickmehr ◽  
Maryam Kazemi
Keyword(s):  
Rheological Property ◽  
Room Temperature ◽  
Aging Study

Synthesis of Hydroxyapatite – Hyaluronic acid Nano Composite Sol under Well-Controlled Condition

2003 ◽  
Vol 788 ◽  
Author(s):  
Yuko Ishikawa ◽  
Mamoru Senna
Keyword(s):  
Hyaluronic Acid ◽  
Aspect Ratio ◽  
Rheological Property ◽  
Ir Spectra ◽  
Electrostatic Interactions ◽  
Room Temperature ◽  
Lattice Parameters ◽  
Nano Composite ◽  
Nucleation Sites ◽  
Ft Ir

ABSTRACTHydroxyapatite (HAp) – Hyaluronic acid (HYA) nano composite sol was prepared at room temperature, at pH 8, by a coprecipitation method from CaCl2 or Ca(CH3COO)2 and H3PO4. These soluble Ca sources were used in order to increase the number of nucleation sites for HAp on HYA. Starting materials were supplied by two kinds of processes to give solution(s) of only PO43- or, PO43- and Ca2+ simultaneously into HYA solution containing Ca2+. Morphology of the aggregates and crystallite size as well as lattice parameters of the HAp were examined by TEM and XRD data with Rietveld refinement. We observed needle like aggregates of crystallites of HAp. Supplying methods of Ca sources controlled the aspect ratio of the aggregates and HAp crystallite. Lattice parameters of the samples prepared from CaCl2 shifted towards those of chloroapatite. Those from Ca(CH3COO)2, however, correspond to the literature values of single crystal HAp. The results of FT-IR spectra and the changes of rheological property indicate the electrostatic interactions between negatively charged functional groups of HYA and HAp.

Thin Films Stress Aging Study using Micromachined Cantilevers

2004 ◽  
Vol 854 ◽  
Author(s):  
Christophe Malhaire ◽  
Alexandru Andrei ◽  
Sebastiano Brida ◽  
Daniel Barbier
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Silicon Oxide ◽  
Harsh Environment ◽  
Determination Method ◽  
Stress Determination ◽  
3D Finite Element ◽  
Aging Study ◽  
C 30

ABSTRACTThe purpose of the present work was to study the long term stress stability of thin films used in harsh environment sensors. A stress determination method, based on cantilevers curvatures measurements, checked by means of 3D finite element simulations, has been proposed. Stress measurements for dielectric (silicon oxide and nitride) and metallic (AlTi and TiW) thin films have been periodically performed at room temperature, after standard annealing (450°C / 30 min in a N2+H2 atmosphere) and after 4 weeks thermal aging at 150°C or 200°C.

Characteristics of tin whiskers formed on sputter-deposited films—an aging study

2004 ◽  
Vol 19 (3) ◽  
pp. 689-692 ◽  
Author(s):  
J.P. Winterstein ◽  
J.B. LeBret ◽  
M.G. Norton
Keyword(s):  
Room Temperature ◽  
Continuous Process ◽  
Nucleation And Growth ◽  
Tin Whiskers ◽  
High Temperature Annealing ◽  
Annealing Conditions ◽  
Aging Study ◽  
Sputter Deposited ◽  
Deposited Films

Tin whiskers formed on sputter-deposited films on Muntz metal substrates have been examined following long-term aging at room temperature. It was found that while the initial annealing conditions determined the original nucleation and growth rates, whisker nucleation and growth was a continuous process and appeared to be occurring throughout the duration of the study. Whisker densities increased for all samples during aging, and samples that initially showed no whiskers during high-temperature annealing had a population density of 2.5 mm−2 after storage for 15 months.

scholarly journals Research on Rheology and Micro-properties of Modified Room Temperature Biological Asphalt

2022 ◽  
Vol 2152 (1) ◽  
pp. 012012
Author(s):  
Yang Shi ◽  
Wen Wang ◽  
Liujie Guo ◽  
Jiusu Li
Keyword(s):  
Rheological Property ◽  
Calcium Hydroxide ◽  
Room Temperature ◽  
Unsaturated Fatty Acids ◽  
Raw Materials ◽  
Curing Agent ◽  
Petroleum Asphalt ◽  
Waste Rubber ◽  
Waste Rubber Powder

Abstract In order to explore the rheological property and principles of modified room temperature biological asphalt made with petroleum asphalt, vegetable asphalt, and unsaturated fatty acids as raw materials, waste rubber powder as modifier, and calcium hydroxide powder as curing agent, this paper compared and tested the rheological properties and the original petroleum asphalt by using DSR and BBR, and the micro-properties of the asphalt were studied by using SEM. The PG classification of modified room temperature biological asphalt has been upgraded from PG58-28 of the original petroleum asphalt to PG82-28. Compared with the original petroleum asphalt, the high temperature rheological property of the modified room temperature biological asphalt has been greatly improved. Its low temperature rheological property is equivalent to the original one, but the possibility of cracking is lower. SEM test showed that the components of the modified room temperature biological asphalt are well combined. The calcium hydroxide curing agent reacts with fatty acid and the rubber particles cross link with each other to form a mesh package in the asphalt, which provides strength for the modified temperature biologic asphalt at room temperature.

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

Hepatocyte Alterations in Guinea Pigs FED Polychlorinated Biphenyls (PCBs), Dibenzodioxins (PCDD), AND DIBENZOFURANS (PCDF)

1982 ◽  
Vol 40 ◽  
pp. 56-57
Author(s):  
J. N. Turner ◽  
D. N. Collins
Keyword(s):  
Guinea Pigs ◽  
Room Temperature ◽  
Dose Group ◽  
Methyl Cellulose ◽  
Uranyl Acetate ◽  
Target Organ ◽  
Office Building ◽  
Lead Citrate ◽  
Control Groups ◽  
Cooling Fluid

A fire involving an electric service transformer and its cooling fluid, a mixture of PCBs and chlorinated benzenes, contaminated an office building with a fine soot. Chemical analysis showed PCDDs and PCDFs including the highly toxic tetra isomers. Guinea pigs were chosen as an experimental animal to test the soot's toxicity because of their sensitivity to these compounds, and the liver was examined because it is a target organ. The soot was suspended in 0.75% methyl cellulose and administered in a single dose by gavage at levels of 1,10,100, and 500mgm soot/kgm body weight. Each dose group was composed of 6 males and 6 females. Control groups included 12 (6 male, 6 female) animals fed activated carbon in methyl cellulose, 6 males fed methyl cellulose, and 16 males and 10 females untreated. The guinea pigs were sacrificed at 42 days by suffocation in CO2. Liver samples were immediately immersed and minced in 2% gluteraldehyde in cacadylate buffer at pH 7.4 and 4°C. After overnight fixation, samples were postfixed in 1% OsO4 in cacodylate for 1 hr at room temperature, embedded in epon, sectioned and stained with uranyl acetate and lead citrate.

Domain Formation in Synthetic Quartz

1971 ◽  
Vol 29 ◽  
pp. 156-157
Author(s):  
Joseph J. Comer
Keyword(s):  
Electron Beam ◽  
Room Temperature ◽  
Domain Formation ◽  
Synthetic Quartz ◽  
Transmission Electron ◽  
Black Spots ◽  
Diffraction Mode ◽  
Domain Boundaries ◽  
Kikuchi Lines ◽  
Straight Lines

Domains visible by transmission electron microscopy, believed to be Dauphiné inversion twins, were found in some specimens of synthetic quartz heated to 680°C and cooled to room temperature. With the electron beam close to parallel to the [0001] direction the domain boundaries appeared as straight lines normal to <100> and <410> or <510> directions. In the selected area diffraction mode, a shift of the Kikuchi lines was observed when the electron beam was made to traverse the specimen across a boundary. This shift indicates a change in orientation which accounts for the visibility of the domain by diffraction contrast when the specimen is tilted. Upon exposure to a 100 KV electron beam with a flux of 5x 1018 electrons/cm2sec the boundaries are rapidly decorated by radiation damage centers appearing as black spots. Similar crystallographio boundaries were sometimes found in unannealed (0001) quartz damaged by electrons.

A Liquid Nitrogen Cooled Stage for STEM

1974 ◽  
Vol 32 ◽  
pp. 444-445
Author(s):  
Louis T. Germinario
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Liquid Nitrogen ◽  
Room Temperature ◽  
Objective Lens ◽  
Thermal Drift ◽  
Specimen Holder ◽  
Resolution Capability ◽  
Focal Position

A liquid nitrogen stage has been developed for the JEOL JEM-100B electron microscope equipped with a scanning attachment. The design is a modification of the standard JEM-100B SEM specimen holder with specimen cooling to any temperatures In the range ~ 55°K to room temperature. Since the specimen plane is maintained at the ‘high resolution’ focal position of the objective lens and ‘bumping’ and thermal drift la minimized by supercooling the liquid nitrogen, the high resolution capability of the microscope is maintained (Fig.4).

Cryogenic atomic force microscopy

1991 ◽  
Vol 49 ◽  
pp. 54-55
Author(s):  
K. A. Fisher ◽  
M. G. L. Gustafsson ◽  
M. B. Shattuck ◽  
J. Clarke
Keyword(s):  
Room Temperature ◽  
Rapid Freezing ◽  
Cryogenic Temperatures ◽  
Soft Or ◽  
Electrically Conductive ◽  
Force Microscopy ◽  
Flexible Molecules ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Chemical Perturbation

The atomic force microscope (AFM) is capable of imaging electrically conductive and non-conductive surfaces at atomic resolution. When used to image biological samples, however, lateral resolution is often limited to nanometer levels, due primarily to AFM tip/sample interactions. Several approaches to immobilize and stabilize soft or flexible molecules for AFM have been examined, notably, tethering coating, and freezing. Although each approach has its advantages and disadvantages, rapid freezing techniques have the special advantage of avoiding chemical perturbation, and minimizing physical disruption of the sample. Scanning with an AFM at cryogenic temperatures has the potential to image frozen biomolecules at high resolution. We have constructed a force microscope capable of operating immersed in liquid n-pentane and have tested its performance at room temperature with carbon and metal-coated samples, and at 143° K with uncoated ferritin and purple membrane (PM).

Benzylamine Tartrate as an Organic Glass Substrate for Carbon Films by Evaporation

1970 ◽  
Vol 28 ◽  
pp. 484-485
Author(s):  
A. C. Faberge
Keyword(s):  
Vapor Pressure ◽  
Viscous Liquid ◽  
Glass Substrate ◽  
Room Temperature ◽  
Carbon Film ◽  
Carbon Films ◽  
Organic Glass ◽  
Spectroscopic Examination ◽  
Polymeric Substrates

Benzylamine tartrate (m.p. 63°C) seems to be a better and more convenient substrate for making carbon films than any of those previously proposed. Using it in the manner described, it is easy consistently to make batches of specimen grids as open as 200 mesh with no broken squares, and without individual handling of the grids. Benzylamine tartrate (hereafter called B.T.) is a viscous liquid when molten, which sets to a glass. Unlike polymeric substrates it does not swell before dissolving; such swelling of the substrate seems to be a principal cause of breakage of carbon film. Mass spectroscopic examination indicates a vapor pressure less than 10−9 Torr at room temperature.

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