scholarly journals Effect of Different Hydrothermal Treatments (Steam and Hot Compressed Water) on Physical Properties and Drying Behavior of Yellow-Poplar (Liriodendron tulipifera)

2019 ◽  
Vol 69 (1) ◽  
pp. 42-52
Author(s):  
Sohrab Rahimi ◽  
Kaushlendra Singh ◽  
David DeVallance
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Moisture Content ◽  
Yellow Poplar ◽  
Pressure Steam ◽  
Percent Moisture ◽  
Drying Behavior ◽  
Hot Compressed Water ◽  
And Control ◽  
Control Samples

Abstract Nonchemical high-pressure steam treatments have been intensively researched and commercialized to produce chemical-free wood products with enhanced properties. However, the utilization of high-pressure steam involves vapor-phase reactions using high-temperature steam generated at the expense of high energy input. In this research, influences of reaction media (steam and hot-compressed water) and temperature (100°C and 140°C) during thermal treatment on physical properties and drying behavior of yellow-poplar (Liriodendron tulipifera) heartwood were compared. The length, width, and thickness of the samples were 22.53 mm, 17.18 mm, and 16.72 mm, respectively. After the treatment, the samples were dried under an isothermal temperature condition of 105°C. Data on moisture content and time of drying from drying experiments were fitted with unsteady-state molecular transport equations to calculate overall liquid diffusion coefficients. Dimensions, weight, and true volume of samples were measured for green, thermally treated, and dried samples and the values were used to calculate selected physical characteristics. Additionally, selected mechanical properties were evaluated for samples conditioned to 13 percent moisture content. Results showed that intensified hot-compressed water-treated and control samples had the highest and lowest saturated moisture contents (101% and 44%), respectively, immediately after treatments. Intensified steam-treated and control samples had the highest and lowest total porosity (95% and 82%), respectively. Furthermore, mild hot-compressed water-treated samples showed the greatest compression strength (47.8 MPa) at 13 percent moisture content. Except for steam treatment at 140°C, other treatments significantly decreased the diffusion coefficient. Collectively, samples treated with hot-compressed water at 100°C showed the most improved mechanical properties.

Automatic Moisture Sensor for Measurement and Control of Cotton Ginning Processes

1983 ◽  
Vol 105 (1) ◽  
pp. 27-30 ◽  
Author(s):  
A. H. Waldie ◽  
S. E. Hughs ◽  
M. N. Gillum
Keyword(s):  
Dielectric Constant ◽  
Process Control ◽  
Moisture Content ◽  
Cotton Fiber ◽  
Sufficient Accuracy ◽  
Moisture Sensor ◽  
Percent Moisture ◽  
And Control ◽  
Measurement And Control ◽  
Conventional Oven

Cotton fiber moisture content is one of the most important factors that affects the operation of the cotton ginning process. A system has been developed that measures cotton’s dielectric constant and density with sufficient accuracy to indicate moisture content of the fiber during processing. An electronic capacitor and a pneumatic density sensor supply measurements to a microprocessor which combines them into a predicted moisture content. Tests showed that these predicted readings are more precise than conventional oven-moisture determinations and that they can be used for process control in the ranges from 6.5- to 12-percent moisture content.

Dislocations in Norway spruce fibres and their effect on properties of pulp and paper

Holzforschung ◽  
2005 ◽  
Vol 59 (2) ◽  
pp. 163-169 ◽  
Author(s):  
Nasko Terziev ◽  
Geoffrey Daniel ◽  
Ann Marklund
Keyword(s):  
Mechanical Properties ◽  
Moisture Content ◽  
Norway Spruce ◽  
Juvenile Wood ◽  
Practical Importance ◽  
Pulp And Paper ◽  
Worst Case ◽  
Machine Failure ◽  
Wood Fibres ◽  
Control Samples

Abstract Wood “cell-wall deformation” is a comprehensive term describing any physical dislocation in the wall caused by mechanical forces. The development and effect of fibre dislocations on wood fibres, and their ultimate impact on the mechanical properties of paper remain rather obscure and controversial. Dislocations are difficult to quantify through a lack of defined measurable features, and research is aggravated by the inherent difficulties of applying statistical tools. A direct approach for studying the effect of dislocations on the mechanical properties of paper was used in this study. Dislocations in fibre cell walls were introduced by exposing whole wood fibres in mature and juvenile wood samples to compression stress. Sapwood samples of Norway spruce (Picea abies Karst.) were loaded by compression to their ultimate strength using an Alwetron-50 universal testing machine. Failure of samples conditioned to a moisture content of 9–15% always occurred in an oblique (relative to the fibre axis) plane and all fibres in the plane were deformed. When samples were loaded in a wet condition (i.e., moisture content close to the fibre saturation point), failure occurred at one end of the samples, resulting in highly disorganised fibres. Pulp and paper from the compressed fibres were produced and the mechanical properties of the paper were tested. Results of the mechanical tests were compared statistically to results derived from paper made from matched non-compressed control samples. Morphological features of fibres and dislocations after compression failure were characterised using microscopy (scanning electron microscopy, polarised light) on the whole wood and macerated fibres before and after paper testing. The above experimental approach showed that paper made from control samples had significantly better mechanical properties than paper made from samples loaded by compression under dry or wet conditions. At a tensile index of 90 N m/g, the tear index was measured as 23.6 mN m2/g for controls, while the corresponding values for compressed wet wood samples was 12.6 and 16.3 mN m2/g for samples at 9–15% moisture content. Paper made from juvenile wood also showed lower mechanical properties compared to controls. The results prove the negative effect of dislocations on the mechanical properties of paper in the worst case scenario and are of practical importance.

scholarly journals Variability in the mechanical properties of commercially available thermally modified hardwood lumber

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 6083-6099
Author(s):  
Juan J. Gonzalez ◽  
Brian Bond ◽  
Henry Quesada
Keyword(s):  
Mechanical Properties ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Untreated Wood ◽  
Red Maple ◽  
Yellow Poplar ◽  
Bending Modulus ◽  
Tangential Shrinkage ◽  
Improved Performance ◽  
Mechanical Performances

Research indicates that users of thermally modified wood lack information regarding the improved performance and any variations that may exist for the “same” product when manufactured by different companies. The goal of this study was to evaluate the variability in mechanical properties of three thermally modified hardwoods and determine the variability between three different manufacturers. To determine the hardness, bending (modulus of elasticity and module of rupture) and shrinkage values, testing was conducted following ASTM standard D143. The samples were conditioned at 20 °C and a relative humidity of 65% until they reached an equilibrium moisture content before testing. Analysis of variance was used to determine the variability within and between the different processes used by each company. Seven out of 18 (39%) tests indicated that there were statistical differences regarding the mechanical performances of the wood samples. Yellow poplar had the least variation between companies (only difference in equilibrium moisture content, EMC) and red maple had the most (hardness, tangential shrinkage, and EMC). While the means for these properties were statistically different, the differences in application for hardness and EMC are slight. For example, the largest difference between processes in hardness was 83.6 kg, for tangential shrinkage, 0.45% and 1.37% for EMC. These differences are suggested to be inconsequential when compared to the values that exist between different species of untreated wood.

Effect of moisture upon mechanical properties of ceramic moulds during high pressure steam dewaxing

2003 ◽  
Vol 19 (7) ◽  
pp. 907-914 ◽  
Author(s):  
S. Jones ◽  
M. R. Jolly ◽  
S. Blackburn ◽  
J.-C. Gebelin ◽  
A. Cendrowicz ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
High Pressure Steam ◽  
Pressure Steam ◽  
Effect Of Moisture

DRIED WHOLE EGG POWDER: XIX. ACCELERATED STORAGE TESTS TO ASSESS THE EFFECT OF HEAT TREATMENT, MOISTURE CONTENT, AND MATERIALS ON THE QUALITY OF DRIED SUGAR–EGG MIXTURES

1946 ◽  
Vol 24f (3) ◽  
pp. 168-182 ◽  
Author(s):  
R. L. Hay ◽  
Jesse A. Pearce
Keyword(s):  
Moisture Content ◽  
Marked Effect ◽  
Shell Eggs ◽  
Accelerated Storage ◽  
Egg Powder ◽  
And Control ◽  
Whole Egg ◽  
Secondary Fluorescence ◽  
Control Samples

Deterioration in quality was assessed by fluorescence, potassium chloride, pH and foaming volume measurements.Dried egg powder (moisture content, 2.8%), containing 33% sugar, and control samples of plain egg powder (moisture content, 3.9%) were stored at temperatures of 80°, 100°, 120°, and 140° F. for seven days. At 140° F. the addition of sugar inhibited the initial, but not the secondary, fluorescence development observed m the plain egg powder and retarded deterioration as assessed by other measurements. At temperatures of 120° F. and lower, the presence of sugar had a marked effect in retarding decrease in quality in egg powder as assessed by all quality tests used. Interpretation of the results in terms of commercial drying practices indicated that cooling shortly after drying was less important for sugar–egg powder than it was for plain egg powder.Dried egg powder containing 33% sugar was adjusted to moisture levels of 1.4, 2.8, and 3.2% and stored at 80° and 120° F. for seven days. The rate of deterioration in quality of sugar–egg powder increased markedly with both moisture content and temperature. Egg powder containing 1.4% moisture maintained higher quality at both temperatures for a longer period than powders at either 2.8 or 3.2% moisture levels. It is recommended that sugar–egg powder be dried to the lowest moisture content compatible with the production of good quality powder, certainly to a moisture content of less than 2.8%, and preferably to 1.4%.Loss in quality was less for sugar–egg powders (moisture content, approximately, 2.3%) prepared with granulated sugar than for those prepared with sucrose syrup, when stored at 80°, 100°, 120°, and 140° F. for seven days. In addition, powder made from fresh shell eggs was more desirable than powder prepared from frozen melange. It is recommended that sugar–egg powder be prepared from a mixture of sugar in granulated form and melange from fresh shell eggs.

Changes in the Population Density of Pathogenic Microorganisms in Response to the Allelopathic Effect of Thypha Latifolia

2014 ◽  
Vol 1 (1) ◽  
pp. 31-36 ◽  
Author(s):  
O. Zhukorskiy ◽  
O. Gulay ◽  
V. Gulay ◽  
N. Tkachuk
Keyword(s):  
Cell Density ◽  
Allelopathic Effect ◽  
Pathogenic Microorganisms ◽  
Sterile Water ◽  
Erysipelothrix Rhusiopathiae ◽  
Pathogenic Leptospira ◽  
Favorable Conditions ◽  
And Control ◽  
The Impact ◽  
Control Samples

Aim. To determine the response of the populations of Erysipelothrix rhusiopathiae and Leptospira interrogans pathogenic microorganisms to the impact of broadleaf cattail (Thypha latifolia) root diffusates. Methods. Aqueous solutions of T. latifolia root diffusates were sterilized by vacuum fi ltration through the fi lters with 0.2-micron pore diameter. The experimental samples contained cattail secretions, sterile water, and cultures of E. rhusiopathiae or L. interrogans. The same amount of sterile water, as in the experimental samples, was used for the purpose of control, and the same quantity of microbial cultures was added in it. After exposure, the density of cells in the experimental and control samples was determined. Results. Root diffusates of T. latifolia caused an increase in cell density in the populations of E. rhusiopathiae throughout the whole range of the studied dilutions (1:10–1:10000). In the populations of the 6 studied serological variants of L. interrogans spirochetes (pomona, grippotyphosa, copenhageni, kabura, tarassovi, canicola), the action of broadleaf cattail root diffusates caused the decrease in cell density. A stimulatory effect was marked in the experimental samples of the pollonica serological variant of leptospira. Conclusions. The populations of E. rhusiopathiae and L. interrogans pathogenic microorganisms respond to the allelopathic effect of Thypha latifolia by changing the cell density. The obtained results provide the background to assume that broadleaf cattail thickets create favorable conditions for the existence of E. rhusiopathiae pathogen bacteria. The reduced cell density of L. interrogans in the experimental samples compared to the control samples observed under the infl uence of T. latifolia root diffusates suggests that reservoirs with broadleaf cattail thickets are marked by the unfavorable conditions for the existence of pathogenic leptospira (except L. pollonica).

Effects of Non-uniform Kernel Moisture Content on Moisture Measurement of Corn

2005 ◽  
Vol 1 (1) ◽  
pp. 77-93
Author(s):  
Bíborka Gillay ◽  
David B. Funk
Keyword(s):  
Moisture Content ◽  
Moisture Measurement ◽  
Safe Storage ◽  
Grain Moisture ◽  
Moisture Meter ◽  
Percent Moisture ◽  
New Crop ◽  
The U.S

The price paid for corn is usually based on 15.0 or 15.5 percent moisture content. However, corn must be dried below 13 percent moisture to ensure safe storage for a year or more. In the U.S., such stored corn cannot be directly remoistened before selling it, but it can be mixed with moist new-crop corn. Accurate moisture measurement of mixtures of dry and moist corn is important to permit adjustment of blending ratios to maximize profitability, but grain moisture meters are less accurate for mixtures of wet and dry grain. This research evaluated the differences between dielectric-type moisture meter results for mixed and equilibrated corn samples at different moisture levels and different measurement frequencies. Equilibrated grain samples tended to give lower moisture results than recently mixed grain samples - especially in the 1 to 10 MHz region. These differences permitted detection of mixtures by using moisture measurements at two frequencies.

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