Extensional Rheology and Stability of Gas Cell Walls in Bread Doughs at Elevated Temperatures in Relation to Breadmaking Performance

2003 ◽  
Vol 80 (2) ◽  
pp. 218-224 ◽  
Author(s):  
B. J. Dobraszczyk ◽  
J. Smewing ◽  
M. Albertini ◽  
G. Maesmans ◽  
J. D. Schofield
Keyword(s):  
Cell Walls ◽  
Elevated Temperatures ◽  
Extensional Rheology ◽  
Gas Cell

The Absorptance of Infrared Radiation by Methane at Elevated Temperatures

1996 ◽  
Vol 118 (4) ◽  
pp. 918-923 ◽  
Author(s):  
S. P. Fuss ◽  
O. A. Ezekoye ◽  
M. J. Hall
Keyword(s):  
Large Scale ◽  
Elevated Temperatures ◽  
Narrow Band ◽  
Line Strength ◽  
Model Parameters ◽  
Band Model ◽  
Gas Cell ◽  
Hydrocarbon Gases ◽  
Ftir Spectrometer ◽  
Path Lengths

In large-scale fires and flames, radiative transport can be an important factor determining the rate of fuel volatilization and flame spread in condensed fuels, and in general can affect the amount of soot that is produced by the flame. The radiant flux can be significantly attenuated by core hydrocarbon gases that have absorption features in the infrared. The spectral absorptance of the υ3 (centered at approximately 3020 cm−l) and υ4 (centered at approximately 1306 cm−l) fundamental bands of methane were measured at elevated temperatures. The measurements were made using a FTIR spectrometer coupled to a gas cell that was maintained at a constant temperature in a furnace. The partial pressure of the methane was varied between 5 and 95 percent, yielding pressure path lengths between 1.14 and 21.72 atm-cm. The total pressure was maintained at 1 atm. Measurements were made at temperatures between 296 and 900 K. The effect of spectral resolution on the measurements and derived parameters was examined. Spectral resolutions between 4 and 32 cm−1 were used. The spectral mean parameters of line strength and line shape were determined for the Elsasser narrow band radiation model using the data taken at a resolution of 4 cm−1. The band model parameters were incorporated into RADCAL, a narrow band model used to predict spectral intensity and transmittance. The results are compared with lower resolution predictions and experimental spectral transmittance data. Tabulated narrow band parameters are available on the Internet (WWW) at URL http://www.me.utexas.edu/~combust/students/paul/research.

The effect of temperature on lysis of cells and cell walls of Bacillus psychrophilus

1971 ◽  
Vol 17 (9) ◽  
pp. 1161-1168 ◽  
Author(s):  
Stephen J. Mattingly ◽  
Gary K. Best
Keyword(s):  
Cell Wall ◽  
Growth Temperature ◽  
Cell Walls ◽  
Elevated Temperatures ◽  
Maximum Growth ◽  
Zero Order ◽  
Effect Of Temperature ◽  
Temperature Dependent ◽  
Maximum Growth Temperature ◽  
Cell Wall Lysis

Cells of Bacillus psychrophilus lysed rapidly when suspended in carbonate or phosphate buffer at a temperature above the maximum growth temperature (30C). This lysis was found to be temperature dependent. The effect of various inhibitors of whole cell lysis was examined. D-Serine, CaCl2, sucrose, and polyethylene glycol were found to be quite effective in inhibiting lysis at 37C. However, this inhibition seemed to be nonspecific. Lysis of isolated cell walls of this psychrophile was also found to be temperature dependent. Lysis was linear and zero order throughout the growth range of this organism. However, as the temperature was increased (37 and 45C) the rate of lysis increased rapidly and zero-order kinetics was lost at these elevated temperatures. D-Aspartic acid was the most effective inhibitor of cell wall lysis. However, its action was only apparent at temperatures above the maximum growth temperature. These results suggest that the cell wall of B. psychrophilus is unusually heat labile and indicate a novel mechanism of lysis.

scholarly journals The role of lignin in wood working processes using elevated temperatures: an abbreviated literature survey

2020 ◽  
Author(s):  
Zoltán Börcsök ◽  
Zoltán Pásztory
Keyword(s):  
Cell Walls ◽  
Elevated Temperatures ◽  
Three Dimensional ◽  
Solid Wood ◽  
Literature Survey ◽  
Industrial Processes ◽  
Dimensional Structure ◽  
Advantages And Disadvantages ◽  
Surface Densification

AbstractThe lignin, cellulose and hemicelluloses in wood are polymers that behave similarly to the artificial polymers and are bonded together in wood. Lignin differs from the other two substances by its highly branched, amorphous, three-dimensional structure. Under appropriate conditions, the moist lignin incorporated in the wood softens at about 100 °C and allows the molecules of it to deform in the cell walls. There are many advantages and disadvantages to this phenomenon. If we know this process accurately and the industrial areas where it matters, we may be able to improve these industrial processes. This article provides a brief theoretical summary of lignin softening and the woodworking processes where it plays a role: wood welding, pellet manufacturing, manufacturing binderless boards, solid wood bending, veneer manufacturing, and solid wood surface densification.

Characterization of Rare-Earth Fluoride Anti-Stokes Phosphors by Scanning arid Transmission Electron Microscopy

1971 ◽  
Vol 29 ◽  
pp. 142-143
Author(s):  
N. M. P. Low ◽  
L. E. Brosselard
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Elevated Temperatures ◽  
Stoichiometric Composition ◽  
Rare Earth Ions ◽  
Crystalline Solid ◽  
Precipitation Process ◽  
Rare Earth Fluoride ◽  
Earth Fluoride ◽  
Rare Earth Fluorides

There has been considerable interest over the past several years in materials capable of converting infrared radiation to visible light by means of sequential excitation in two or more steps. Several rare-earth trifluorides (LaF3, YF3, GdF3, and LuF3) containing a small amount of other trivalent rare-earth ions (Yb3+ and Er3+, or Ho3+, or Tm3+) have been found to exhibit such phenomenon. The methods of preparation of these rare-earth fluorides in the crystalline solid form generally involve a co-precipitation process and a subsequent solid state reaction at elevated temperatures. This investigation was undertaken to examine the morphological features of both the precipitated and the thermally treated fluoride powders by both transmission and scanning electron microscopy.Rare-earth oxides of stoichiometric composition were dissolved in nitric acid and the mixed rare-earth fluoride was then coprecipitated out as fine granules by the addition of excess hydrofluoric acid. The precipitated rare-earth fluorides were washed with water, separated from the aqueous solution, and oven-dried.

Ectodesmata as Revealed By Freeze-Etch Preparations of Plant Epidermal Cell Walls

1973 ◽  
Vol 31 ◽  
pp. 468-469
Author(s):  
N.C. Lyon ◽  
W. C. Mueller
Keyword(s):  
Electron Microscopy ◽  
Acetic Acid ◽  
Nitric Acid ◽  
Oxalic Acid ◽  
Light Microscopy ◽  
Epidermal Cell ◽  
Cell Walls ◽  
Plant Viruses ◽  
Plant Leaves ◽  
Thin Sections

Schumacher and Halbsguth first demonstrated ectodesmata as pores or channels in the epidermal cell walls in haustoria of Cuscuta odorata L. by light microscopy in tissues fixed in a sublimate fixative (30% ethyl alcohol, 30 ml:glacial acetic acid, 10 ml: 65% nitric acid, 1 ml: 40% formaldehyde, 5 ml: oxalic acid, 2 g: mecuric chloride to saturation 2-3 g). Other workers have published electron micrographs of structures transversing the outer epidermal cell in thin sections of plant leaves that have been interpreted as ectodesmata. Such structures are evident following treatment with Hg++ or Ag+ salts and are only rarely observed by electron microscopy. If ectodesmata exist without such treatment, and are not artefacts, they would afford natural pathways of entry for applied foliar solutions and plant viruses.

An ultrastructural study of vegetative incompatibility in plants

1978 ◽  
Vol 36 (2) ◽  
pp. 436-437
Author(s):  
Randy Moore
Keyword(s):  
Ultrastructural Study ◽  
Cell Walls ◽  
Growth And Development ◽  
Solanum Pennellii ◽  
Initial Product ◽  
Basic Aspect ◽  
Tissue Interactions ◽  
Graft Interface ◽  
Antigen Antibody ◽  
Standard Fixation

Cell and tissue interactions are a basic aspect of eukaryotic growth and development. While cell-to-cell interactions involving recognition and incompatibility have been studied extensively in animals, there is no known antigen-antibody reaction in plants and the recognition mechanisms operating in plant grafts have been virtually neglected.An ultrastructural study of the Sedum telephoides/Solanum pennellii graft was undertaken to define possible mechanisms of plant graft incompatibility. Grafts were surgically dissected from greenhouse grown plants at various times over 1-4 weeks and prepared for EM employing variations in the standard fixation and embedding procedure. Stock and scion adhere within 6 days after grafting. Following progressive cell senescence in both Sedum and Solanum, the graft interface appears as a band of 8-11 crushed cells after 2 weeks (Fig. 1, I). Trapped between the buckled cell walls are densely staining cytoplasmic remnants and residual starch grains, an initial product of wound reactions in plants.

Observations oh Nucleation and Growth of Voids in Nickel

1970 ◽  
Vol 28 ◽  
pp. 414-415
Author(s):  
J. L. Brimhall ◽  
H. E. Kissinger ◽  
B. Mastel
Keyword(s):  
High Purity ◽  
Growth Stage ◽  
Elevated Temperatures ◽  
Early Growth ◽  
Nucleation And Growth ◽  
Pure Nickel ◽  
Different Temperatures ◽  
Total Fluence ◽  
Neutron Exposure ◽  
Growth Of Voids

Some information on the size and density of voids that develop in several high purity metals and alloys during irradiation with neutrons at elevated temperatures has been reported as a function of irradiation parameters. An area of particular interest is the nucleation and early growth stage of voids. It is the purpose of this paper to describe the microstructure in high purity nickel after irradiation to a very low but constant neutron exposure at three different temperatures.Annealed specimens of 99-997% pure nickel in the form of foils 75μ thick were irradiated in a capsule to a total fluence of 2.2 × 1019 n/cm2 (E > 1.0 MeV). The capsule consisted of three temperature zones maintained by heaters and monitored by thermocouples at 350, 400, and 450°C, respectively. The temperature was automatically dropped to 60°C while the reactor was down.

Voids in Irradiated Tungsten and Molybdenum

1969 ◽  
Vol 27 ◽  
pp. 190-191
Author(s):  
Robert C. Rau ◽  
Robert L. Ladd
Keyword(s):  
Melting Point ◽  
Fast Neutron ◽  
Neutron Irradiation ◽  
Elevated Temperatures ◽  
Irradiation Temperature ◽  
The Body ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Cubic Metals ◽  
Face Centered

Recent studies have shown the presence of voids in several face-centered cubic metals after neutron irradiation at elevated temperatures. These voids were found when the irradiation temperature was above 0.3 Tm where Tm is the absolute melting point, and were ascribed to the agglomeration of lattice vacancies resulting from fast neutron generated displacement cascades. The present paper reports the existence of similar voids in the body-centered cubic metals tungsten and molybdenum.

Mechanical Properties and Dislocation Structure of Single Crystal Cdte Deformed in Compression at 300°C

1976 ◽  
Vol 34 ◽  
pp. 592-593
Author(s):  
Ernest L. Hall ◽  
J. B. Vander Sande
Keyword(s):  
Mechanical Properties ◽  
Single Crystal ◽  
Dislocation Structure ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Optical Devices ◽  
Semiconductor Compound ◽  
Wide Range ◽  
Sample Orientation

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.

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