Study of Factors Affecting the Ablation Rate of Phenolic Resin/Fiber Glass

The effect of SiBCN powder on properties of phenolic resins and composites was analyzed. Compared with phenolic resins, the thermal stability of SiBCN powder modified phenolic resins (the SiBCN phenolic resins) by characterization of thermogravimetric analysis (TGA) improved clearly. It was found by X-ray photoelectron spectroscopy (XPS) that reactions between SiBCN powder and the pyrolysis product of phenolic resins were the main factor of the increased residual weight. TGA and static ablation of a muffle furnace were used to illustrate the roles of SiBCN powder on increasing oxidation resistance of SiBCN powder-modified phenolic resin–carbon fiber composites (SiBCN–phenolic/C composites), and the oxidative product was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). For SiBCN–phenolic/C composites, the occurrence of oxidation reaction and the formation of protective crust contributed to improving oxidative resistance. The result of the oxygen-acetylene test showed that the linear ablation rate (LAR) and mass ablation rate (MAR) of phenolic resin–carbon fiber composites reduced from 0.052 ± 0.005 mm/s to 0.038 ± 0.004 mm/s and from 0.050 ± 0.004 g/s to 0.043 ± 0.001 g/s by introducing SiBCN powder, respectively. The mechanism of ablation resistance after the introduction of SiBCN powder was investigated. The high melt-viscosity of SiBCN powder caused SiBCN powder to remain on the surface of composites and protect the internal resins and carbon fibers. The oxidation of SiBCN powder and volatilization of oxide can consume energy and oxygen, thus the ablation resistance of SiBCN–Ph composite was improved.

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Thermal and Mechanical Properties of Boron-Containing Bisphenal-A Formaldehyde Resin Composites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.150-151.877 ◽

2010 ◽

Vol 150-151 ◽

pp. 877-880

Author(s):

Jun Gang Gao ◽

Xing Li ◽

Bei Bei Sun

Keyword(s):

Mechanical Properties ◽

Bisphenol A ◽

Surface Resistance ◽

Phenolic Resin ◽

Volume Resistivity ◽

Formaldehyde Resin ◽

Resin Composites ◽

Thermal And Mechanical Properties ◽

Fiber Glass ◽

Residual Rate

Boron-containing bisphenol-A formaldehyde resin (BBAFR) with different amounts of boron was synthesized from bisphenol-A, formaldehyde solution and boric acid. The fiber-glass reinforced laminates were prepared. The thermal, electric and mechanical properties were determined. The results show that the BBAFR has a better thermal stablitity. The residual rate of BBAFR is 18% at 900 oC, which is higher 300 oC than ordinary phenolic resin. The tensile strength of BBAFR fiber-glass laminates is higher 19.07MPa than ordinary phenolic resin fiber-glass laminates. The volume resistivity and surface resistance of BBAFR laminates increased, but the dielectric loss tanδ and dielectric constant ε decreased.

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Study on cement based composite board of wire mesh and straw fibers in severe cold area of Northeast China

10.21203/rs.3.rs-145550/v1 ◽

2021 ◽

Author(s):

Jie Liu ◽

Chun Lv

Keyword(s):

Carbon Steel ◽

Northeast China ◽

Steel Wire ◽

Low Carbon Steel ◽

Wire Mesh ◽

Alkali Resistance ◽

Flexural Property ◽

Low Carbon ◽

Fiber Glass ◽

Factors Affecting

Abstract There is a large amount of residual straw fibers resources in Northeast China. Rice straw fibers was chosen to make steel-wire-net mortar roof-board composed of straw fibers in different sizes. Cold-drawn and low-carbon steel-wire-nets, whose diameter was 3mm and whose size of mesh opening was 60mm×60mm ,were set on both upper and lower sides. Vertical tied cold-drawn low-carbon wires were set between the upper and lower cold-drawn and low-carbon steel-wire-lath for spot welding. The distance between two vertical tied steel wires was 120mm. After the mortar was squirted on the steel-wire-nets, outbound alkali resistance fiber glass mesh and thin floated finish make the alkali resistance fiber glass mesh and thin plastering mortar and horizontal wire mesh mortar and compressed straw fibers slab straw fibersboard work together. The deformation characteristics that studies roof-board composed of straw fibers boards; the fracture distribution and the feature of crack developing that studies the boards; the strain distribution and its change law were summarized, the loading mechanism of roof-board composed of straw fibers boards had been studied; by observing the failure form and destruction feature of test specimen, the factors affecting the flexural property of roof-board composed of straw fibers boards had been studied, preparation points of roof-board composed of straw fibers boards had been put forward. The advantages of grass steel-wire-net thin plastering roof-board composed of straw fibers boards reside in cheap materials, moderate carrying capacity and it was easy to be applied.

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ON THE FACTORS AFFECTING THE RATE OF ABLATION OF SEA ICE

Canadian Journal of Earth Sciences ◽

10.1139/e66-032 ◽

1966 ◽

Vol 3 (4) ◽

pp. 431-439 ◽

Cited By ~ 20

Author(s):

M. P. Langleben

Keyword(s):

Sea Ice ◽

Heat Budget ◽

Ice Sheet ◽

Ablation Rate ◽

Shortwave Radiation ◽

Dominant Factor ◽

Wave Radiation ◽

First Year ◽

Factors Affecting ◽

Thermal Content

A study has been made of the heat budget just before and during the season of ablation, of first year sea ice near the head of Tanquary Fiord. Ablation started as the air temperature approached 0 °C, producing a decrease in albedo from approximately 0.6 to 0.2 in less than a week. Typical values of incident shortwave radiation were 800 cal cm−2 day−1 on clear days and 400 cal cm−2 day−1 during heavy overcast. The net influx of all-wave radiation was about 350 cal cm−2 day−1 during the ablation period, and resulted in a rate of ablation of ice of approximately 4 cm day−1.It is shown that the flux of radiative heat is the dominant factor determining the ablation rate and the change in thermal content of the ice sheet. Upward conduction from the sea is small, except when surface melt runoff occurs and collects in a stable layer immediately under the ice sheet. Even partial refreezing in this layer may release large quantities of latent heat to increase the rate of bottom conduction appreciably.

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Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100078614 ◽

1977 ◽

Vol 35 ◽

pp. 214-217

Author(s):

F. A. Heckman ◽

E. Redman ◽

J.E. Connolly

Keyword(s):

Image Analysis ◽

Image Quality ◽

Exposure Time ◽

Image Contrast ◽

Automated Image Analysis ◽

Practical Application ◽

Factors Affecting ◽

High Image Quality ◽

Qualitative Evidence ◽

Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

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Factors affecting microstructural scale in liquid crystalline polymers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100174230 ◽

1990 ◽

Vol 48 (4) ◽

pp. 220-221

Author(s):

Christine M. Dannels ◽

Christopher Viney

Keyword(s):

Liquid Crystalline ◽

Liquid Crystalline Polymers ◽

Factors Affecting ◽

Crystalline Polymers ◽

Thermal Expansion Coefficients ◽

Low Thermal Expansion ◽

Lower Viscosity ◽

Fine Microstructure ◽

Planar Orientation ◽

Strength And Stiffness

Processing polymers from the liquid crystalline state offers several advantages compared to processing from conventional fluids. These include: better axial strength and stiffness in fibers, better planar orientation in films, lower viscosity during processing, low solidification shrinkage of injection moldings (thermotropic processing), and low thermal expansion coefficients. However, the compressive strength of the solid is disappointing. Previous efforts to improve this property have focussed on synthesizing stiffer molecules. The effect of microstructural scale has been overlooked, even though its relevance to the mechanical and physical properties of more traditional materials is well established. By analogy with the behavior of metals and ceramics, one would expect a fine microstructure (i..e. a high density of orientational defects) to be desirable.Also, because much microstructural detail in liquid crystalline polymers occurs on a scale close to the wavelength of light, light is scattered on passing through these materials.

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Factors affecting dentist participation in a state Medicaid program

Journal of Dental Education ◽

10.1002/j.0022-0337.1990.54.11.tb02476.x ◽

1990 ◽

Vol 54 (11) ◽

pp. 638-643 ◽

Cited By ~ 20

Author(s):

PC Damiano ◽

ER Brown ◽

JD Johnson ◽

JP Scheetz

Keyword(s):

Medicaid Program ◽

Factors Affecting

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Factors affecting dental utilization of elders aged 75 years or older

Journal of Dental Education ◽

10.1002/j.0022-0337.1986.50.11.tb02060.x ◽

1986 ◽

Vol 50 (11) ◽

pp. 673-677 ◽

Cited By ~ 5

Author(s):

AA Wilson ◽

LG Branch

Keyword(s):

Factors Affecting ◽

Dental Utilization

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Speech Therapy Services in a Large School System: A Six-Year Overview

Language Speech and Hearing Services in Schools ◽

10.1044/0161-1461.0704.207 ◽

1976 ◽

Vol 7 (4) ◽

pp. 207-219 ◽

Cited By ~ 3

Author(s):

Constance P. DesRoches

Keyword(s):

School System ◽

Speech Therapy ◽

Factors Affecting ◽

Case Load ◽

Number Of Children ◽

School Population ◽

System A ◽

Therapy Services ◽

And Shifts ◽

Selection Factors

A statistical review provides analysis of four years of speech therapy services of a suburban school system which can be used for comparison with other school system programs. Included are data on the percentages of the school population enrolled in therapy, the categories of disabilities and the number of children in each category, the sex and grade-level distribution of those in therapy, and shifts in case-load selection. Factors affecting changes in case-load profiles are identified and discussed.

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