Tensile Creep of Paperboard—Effect of Humidity Change Rates

1990 ◽  
Vol 197 ◽  
Author(s):  
Dennis E. Gunderson ◽  
Wayland E. Tobey
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Cyclic Creep ◽  
Progressive Increase ◽  
Rate Of Change ◽  
Tensile Creep ◽  
Creep Response ◽  
Humidity Change ◽  
Percent Relative Humidity ◽  
Better Than

ABSTRACTExperimental results now available are not adequate to define the mechanism of cyclic creep response of paperboard or to test plausible hypotheses. The present study examines the effect of rate-of-change of humidity on tensile creep response while monitoring the quantities of water adsorbed and desorbed by the specimen. Relative humidity is cycled between 30 and 90 percent relative humidity. Rate of humidity change in each cycle is held constant at values from 0.01 to 6 percent relative humidity per minute. Moisture sorbed by the web in each cycle is resolved to an accuracy better than ±0.05 percent moisture content. Results suggest that cyclic creep response is independent of the rate at which humidity changes. The results appear to reject the hypothesis that cyclic creep behavior is the result of a progressive increase in equilibrium moisture content.

scholarly journals Artifacts in electrical measurements on wood caused by non-uniform moisture distributions

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Maria Fredriksson ◽  
Emil Engelund Thybring ◽  
Samuel L. Zelinka
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Electrical Conductance ◽  
Percolation Model ◽  
Conditioning Procedure ◽  
Electrical Measurements ◽  
Moisture Contents ◽  
Constant Relative Humidity ◽  
Water Saturated ◽  
Better Than

AbstractThis paper examines how the moisture conditioning method affects the electrical conductance of wood. A widely used dataset was acquired by Stamm in 1929 who used a method of conditioning where water-saturated wood specimens were partially dried, sealed and left for a period of time for moisture to be redistributed before the electrical conductance was measured. However, more recent measurements combined conditioning above saturated salt solutions and pressure plate/pressure membrane techniques to obtain equilibrium moisture contents at constant relative humidity levels in the full moisture range. In this paper, the electrical conductance as a function of moisture content was compared for these two conditioning methods. When the specimens were conditioned to constant relative humidity levels, the data obeyed a percolation model better than when the conditioning procedure by Stamm was used. This was attributed to that Stamm’s method gives moisture gradients through the specimen because of sorption hysteresis effects, even though the wood is conditioned to a steady-state moisture content. Equilibration to constant relative humidity levels thus provided more well-defined moisture states and that the data followed a percolation model indicates that the mechanism of electrical conduction in wood does not change, even at high moisture contents.

CATFISH DRYING (Clarias Batraclus) USING ‘TEKO BERSAYAP’ SOLAR DRYER

2012 ◽  
Vol 2 (1) ◽  
pp. 14-20
Author(s):  
Yuwana Yuwana
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Ambient Temperature ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Time ◽  
Ambient Relative Humidity ◽  
Solar Dryer

Experiment on catfish drying employing ‘Teko Bersayap’ solar dryer was conducted. The result of the experiment indicated that the dryer was able to increase ambient temperature up to 44% and decrease ambient relative humidity up to 103%. Fish drying process followed equations : KAu = 74,94 e-0,03t for unsplitted fish and KAb = 79,25 e-0,09t for splitted fish, where KAu = moisture content of unsplitted fish (%), KAb = moisture content of splitted fish (%), t = drying time. Drying of unsplitted fish finished in 43.995 hours while drying of split fish completed in 15.29 hours. Splitting the fish increased 2,877 times drying rate.

scholarly journals Interdisciplinary conversations in STEM education: can faculty understand each other better than their students do?

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jeffrey M. Rabin ◽  
Adam Burgasser ◽  
Thomas J. Bussey ◽  
John Eggers ◽  
Stanley M. Lo ◽  
...  
Keyword(s):  
Cultural Differences ◽  
Stem Education ◽  
Interdisciplinary Collaboration ◽  
Rate Of Change ◽  
Theory And Practice ◽  
College Mathematics ◽  
Instructional Videos ◽  
Interdisciplinary Projects ◽  
Shared Understandings ◽  
Better Than

AbstractRate of change concepts from calculus are presented and applied rather differently in college mathematics, physics, biology, and chemistry classes. This is not simply a matter of pedagogical style but reflects real cultural differences between these disciplines. We describe the efforts of our interdisciplinary collaboration to understand and reconcile these differences as we designed and discussed instructional videos for students. We summarize our conversations about terminology, notation, functions, rates, units, and sign conventions across the disciplines. We present some strategies that enabled us to communicate effectively, resolve confusions, and reach shared understandings. Our work has implications for others involved in collaborative interdisciplinary projects and for STEM educators.In theory, there’s no difference between theory and practice. But in practice, there is.– Benjamin Brewster. Also attributed to Yogi Berra.

Algorithms to predict moisture content of grain using relative humidity time-series

2020 ◽  
Author(s):  
Charles B. Delahunt ◽  
Wenbo Wang ◽  
Simon Ghionea ◽  
Andrew Miller ◽  
Austin Chan ◽  
...  
Keyword(s):  
Time Series ◽  
Relative Humidity ◽  
Moisture Content

Determination of readiness for laying based on material moisture, corresponding relative humidity, and water release

2020 ◽  
Vol 62 (10) ◽  
pp. 1033-1040
Author(s):  
Christoph Strangfeld ◽  
Sabine Kruschwitz
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Embedded Sensors ◽  
Residual Water ◽  
Floor Covering ◽  
Water Release ◽  
Content Determination ◽  
Two Samples ◽  
Moisture Content Determination

Abstract The moisture content of the subfloor has to be determined before installation to avoid damage to the floor covering. Only if readiness for layering is reached, can an installation without damage be expected in all cases. In general, three approaches exist to measure residual water content: determination of moisture content, determination of water release, or determination of the corresponding relative humidity. All three approaches are tested under laboratory conditions at eight screed types including two samples thicknesses in each case. Moisture content and water release are measured by sample weighing, the corresponding relative humidity is measured by embedded sensors. All three approaches are compared and correlated. The evaluations show only a weak correlation and, in several cases, contradicting results. Samples are considered ready for layering and not ready for layering at the same time, depending on the chosen approach. Due to these contradicting results, a general threshold for a risk of damage cannot be derived based on these measurements. Furthermore, the experiment demonstrates that the measurement of corresponding relative humidity is independent of the screed type or screed composition considered. This makes humidity measurement a potentially very promising approach for the installation of material moisture monitoring systems.

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