Paulo Ricardo Gherardi Hein

11 Questions 22 Answers 0 Followers

Questions related from Paulo Ricardo Gherardi Hein

What is the most suitable pulp consistency for taking NIR spectra in order to estimate Schopper Riegler (SR) degree?

The idea behind this study will be investigate how mechanical refining improve strenght of nanocellulosic films. Thus, we would like to record NIR spectra on Eucalyptus pulp for developing models...

08 November 2017 982 1 View

Why do nanometals work better than their soluble metal oxides when used as wood preservatives?

Considering that the wood preservative, eg copper sulfate, will be diluted in water and then impregnated in the wood, why does the product's dimension (nanocupper or copper sulfate) or even...

31 March 2017 3,250 1 View

Why does shrinkage in tangential direction is higher than radial shrinkage during wood drying?

There are many explanations about the reasons why tangential shrinkage is more intense than radial shrinkage when wood dries. After all, what are the main reasons?

03 March 2017 1,337 9 View

How to evaluate the quality and quantity of wood extractives?

What is the most appropriate technique to find out what chemical components are present in wood extractives from native species in Brazil? And what is the best technique to quantify each type of...

21 November 2016 6,446 5 View

PLS-R validation based on NIR spectroscopic data with negative R²: what does it means?

I am developing PLS-R calibrations based on NIR spectra for estimating wood density. When I used a totally independent set of 18 unknown samples to validate this model, I found a negative R² for...

23 July 2016 6,341 4 View

Why wood disks freshly cut split?

If the wood shrinkage takes place below the fiber saturation point, why wood disks cut from freshly felled trees, still saturated, develop cracks? Some colleagues think it is due to growth...

23 July 2015 1,616 4 View

What are the most suitable solvents to extract volatile material from vegetable charcoal?

Dear, I plan to extract the volatile material from vegetable charcoal to further analyze the extract. I thought about doing the extraction with polar and nonpolar solvents. someone might suggest...

01 April 2015 6,194 8 View

Does anyone know how to open/run DPT files (NIR spectroscopic data) in The Unscrambler software?

Does anyone knows how to open/run DPT files (NIR spectroscopic data) in The Unscrambler software?

29 August 2014 9,710 31 View

Drying defects in Eucalyptus wood: what may have caused this ring-collapse?

Dear,I observed a darker zone in ring shape in some of my 6-year-old Eucalyptus wood samples grown in Brazil for pulp and paper industry. Then, I observed an intense shrinkage at the lateral of...

31 July 2014 2,145 12 View

Why is there a certain amount of water-soluble extractives in dried wood, if when this wood was part of a living tree, there was sap flow?

While the wood was part of the standing tree, sap flowed trough their vessels. Thus, how can there be water-soluble extractives in a dried wood sample if many liters of sap have passed by it over...

15 June 2014 4,848 5 View

How deep a NIR spectra can reach in a wood sample? What is the influence of moisture and density of the material on the penetration of the spectrum?

I am taking NIR spectra on wood sections and I would like to know if the spectra are crossing through the 5 mm samples.

13 June 2014 411 2 View