ProLigno / ProLigno 2010 Numarul 2  
     
 
 
   
 

 

 

 

 

 

 

 

DETERMINARE SI CUANTIFICARE NEDISTRUCTIVA A PROCESELOR DE DIFUZIUNE IN LEMN CU AJUTORUL METODEI IMAGISTICE CU NEUTRONI

David MANNES
Dr. - Department of Civil, Environmental and Geomatic Engineering, Institute for Building Materials (ETH) Adresa: 8093 Zurich, Switzerland
Tel: +41 44 632 3228. Fax: +41 44 632 1174.
E-mail: dmannes@ethz.ch

Walter SONDEREGGER
Eng. - Department of Civil, Environmental and Geomatic Engineering,
Institute for Building Materials (ETH)
E-mail: wsonderegger@ethz.ch

Stefan HERING
Eng. - Department of Civil, Environmental and Geomatic Engineering,
Institute for Building Materials (ETH)
E-mail: shering@ethz.ch

Eberhard LEHMANN
Dr. - Spallation Neutron Source (ASQ), Paul Scherrer Institute (PSI)
Adresa: 5232 Villigen, Switzerland
E-mail: eberhard.lehmann@psi.ch

Peter NIEMZ
Prof.Dr. - Dept. of Civil, Environmental and Geomatic Engineering
Institute for Building Materials (ETH)
E-mail: niemzp@ethz.ch

Rezumat:
         Procesele de difuziune in epruvetele de fag (Fagus sylvatica L.) si molid (Picea abies [L.] Karst.) au fost determinate si cuantificate cu ajutorul metodei imagistice cu neutroni (NI). Experimentele s-au efectuat la sediul NEUTRA al Institutului Paul Scherrer (PSI) din Villigen (Elvetia) utilizand un spectru termic cu neutroni. NI este o metoda de testare nedistructiva si neinvaziva, cu o mare senzitivitate pentru hidrogen si astfel pentru apa. Ca scop al acestui studiu, s-au stabilit procesele de difuziune in directie longitudinala la epruvete de lemn masiv expuse in diferite conditii (uscat-umed).Cu ajutorul NI a fost posibila determinarea distrubutiei locale si prin urmare cantitatea totala de apa absorbita de epruvete. Valorile calculate difera relativ putin fata de cele stabilite prin cantarire (= 3%). Metoda da profilul continutului de apa al intregii epruvete, permitand astfel analiza locala si temporala a proceselor de difuziune in cuprinsul epruvetei in aceeasi directie de transport (longitudinala). In baza acestor profiluri a fost posibil sa se calculeze coeficientii de difuziune in directia fibrelor respectand legea a doua a lui Fick.

Cuvinte cheie: difuziune, coeficient de difuziune, umiditate, imagistica cu neutroni, testare nedistructiva, lemn.

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Pagina creata de Costel AGACHE. Intretinere pagina Luminita Brenci. Ultima actualizare, 15 Iulie 2010