ProLigno / ProLigno 2006 Numarul 3  
     
 
 
   

 

 

 

 

 

 

 

We continue within this issue the presentation of the speciality-specific subjects teached at the Faculty of Wood Industry in Brasov. Following up the two basic subjects presented within the previous journal issue, “Fundamentals of Wood Production and Environment Protection”, respectively “Wood Anatomy”, it is now the turn of two other important subjects teached during the 1st and 2nd year of study.

These subjects complete the students knowledge concerning wood as a row material, by presenting them the assembly of its chemical, physical, mechanical, acoustic properties etc, considering that they are essential to be known with a view to a rational use of wood and in order to understand the behaviour of this material during processing and after being included in a finished product.

Subject title: WOOD CHEMISTRY

Semester / Year of study: semester I / year I

Status: compulsory

Objectives:

  • Substantiation of some basic knowledge referring to the main classes of organic chemical compounds with simple and mixt organic functions;
  • Gaining knowledge of the chemical composition of wood, structure and properties of the main and secondary chemical components of wood and bark.

As a whole, the course provides the necessary technical knowledge support for a thoroughgoing study of other related courses following-up during the next semesters of the curricula, such as: physics and mechanics of wood, technical materials for wood industry, technology of particleboards and laminated panel products.

Contents:
The course is divided into two parts:

Part I. Organic chemistry

  • Organic compounds with simple organic functions (definition, nomenclature, classification, physical and chemical properties): Halides. Hydroxyl compounds. Carbonyl compounds. Carboxylic compounds. Functional derivatives of carboxylic acids. Nitrogen containing organic compounds.
  • Organic compounds with mixed organic functions (definition, nomenclature, classification, physical and chemical properties): Phenol-aldehydes and phenol-ketones. Monosaccharides. Oligosaccharides. 
  • Macromolecular compounds (definition, nomenclature, classification, physical and chemical properties).

Part II. Wood chemistry

  • Elementary chemical composition of wood. Main and secondary chemical components of wood and bark. Morphological distribution of these components in the vegetal wooden tissues.
  • Cellulose.
  • Lignin.
  • Hemicelluloses.
  • Secondary chemical components of wood (resins, waxes, fats, vegetal gums, tannins).

The laboratory practical works are also grouped into two cycles, comprising the following:

  • Cycle I. Organic chemistry
    • Basics of volumetric and gravimetric chemical analysis.
    • Determination of acid content of technical organic acids.
    • Determination of aldehyde content of technical aldehydes.
    • Determination of ester content of technical esters.
    • Determination of monomer content and polymerisation time of vinyl monomers.
  • Cycle II. Wood chemistry
    • Determination of wood moisture content by oven-drying method and solvent extraction method.
    • Determination of extractives content of wood
    • Determination of cellulose content in wood.
    • Determination of lignin content in wood.
    • Determination of hemicelluloses content in wood.
    • Determination of ash content in wood.
    • Determination of pentosans content in wood.
    • Analysis of water in wood industry.

History:
The course leader until 1985 was Lecturer Dr. Eng. Sabin Riscuta. The structure of the course at that time was quite similar to the present one, the both parts being, however, preceded by some much more detailed basic theoretical principles. The course included also some aspects related to the chemical wood processing.  

The course name suffered some changes over the years, such as follows: WOOD CHEMISTRY between 1972 – 1980, CHEMISTRY between 1981 – 1994, WOOD CHEMISTRY AND CHEMICAL PROCESSING OF WOOD between 1994 – 2001 and again WOOD CHEMISTRY after 2001. 

Starting from 1986 until now the laboratory practical sessions are lead by Lecturer Dr.Eng. Costel Agache.

Present Head of Discipline:
Valeriu PETROVICI, Professor, PhD, graduate of the Faculty of Industrial Chemistry, Iasi, class 1960
Title of PhD thesis: "Research concerning valorisation in paper industry of residual liquor from the viscose industry". Thesis defended in June 1976 at the Polytechnical Institute “Gh. Asachi”, Iasi.

Publications within the field of the discipline:

  • "Wood Chemistry, course support". Reprography of “Transilvania” University Brasov, 1987.
  • "Wood Chemistry and Chemical Processing of Wood, Vol. I. Organic Chemistry". Printing House Lux Libris, Brasov, 1997.
  • "Wood Chemistry and Chemical Processing of Wood, Vol. II. Wood Chemistry". Printing House Lux Libris, Brasov, 1998.

Awards: since 2004 - PhD supervisor in the fundamental field ENGINEERING SCIENCES, area MATERIALS SCIENCE AND ENGINEERING.

Perspectives and Opportunities:
The future development of the discipline considers the following directions:

  • Enlargement of endowment of the Laboratory of Wood Chemistry of the Faculty of Wood Industry by acquisition of modern chemical analysis equipment: spectrophotometers UV and IR, HPLC chromatograph, thermo-gravimetric analyser etc.
  • Full endowment of the Laboratory for the determination of formaldehyde emission and its accreditation by RENAR – Bucharest, in order to be allowed to perform fully nationally and internationally recognised analyses. In this context, we would like to acknowledge the contribution of the company IKEA TRADING UND DESIGN AG Romania, by sponsoring our Faculty with an installation for the determination of the formaldehyde emission of wooden boards by the chamber method, according to the norm SR EN 717-1: 2005. This is the only one equipment of this type in the South-East of Europe.
  • Editing of the third volume of the book "Wood Chemistry and Chemical Processing of Wood", as well as re-editing a volume of practical works, as useful reference materials for both our students and the specialists from wood industry.

Subject title: WOOD PHYSICS AND MECHANICS

Semester / Year of study: semester I / 2nd year

Status: compulsory

Objective:
The complex structure and chemical composition confers wood special properties, different of those specific to other materials. Among these, the physical properties of wood (moisture, swelling and shrinkage, density), its acoustical, thermal, electrical, technological properties, as well as the wood behaviour under mechanical loads, such as tensile, compression, shearing, torsion, bending stresses have an important role. 

The main objective of this discipline consists of the unitary presentation of these properties, their analysis in concordance with the influencing factors, the reciprocal relationships between different properties, as well as the use of this knowledge in order to find solutions for practical problems.

Contents:
The lectured material is structured on seven chapters:
1.Wood moisture:

  • Terminology and definition
  • Localisation and state of moisture in wood
  • Penetration of water in wood and resulting phenomena
  • Fibre saturation point
  • Equilibrium moisture content, hysteresis of sorption and desorbtion
  • Maximum moisture content of wood
  • Wooden substance, water and air proportion in wood
  • Influence of moisture content on wood properties
  • Determination of wood moisture content

2.Wood swelling and shrinkage:

  • Definition, classification, symbols
  • Swelling and shrinkage coefficients. General calculation relationships
  • Reciprocal relationships between wood swelling, shrinkage and density
  • Swelling and shrinkage coefficients for a moisture variation of the cell membrane by 1%
  • Determination of wood swelling and shrinkage
  • Factors which influence the swelling and shrinkage of wood
  • Accompanying phenomena: swelling heat, swelling pressure, volumetric shrinkage, deformations, collapse
  • Swelling and shrinkage of wooden semi-products (veneers, laminated products, particleboards)
  • Consequences of solid wood swelling and shrinkage in: panel veneering, panel edging, assembling of solid wood frames and panels, as well as glue-laminated timber manufacturing.
  • Dimensional stabilization of wood

3. Wood density

  • Terminology, definition and expressions
  • Density of the wooden substance
  • Density of the cell membrane
  • Apparent density of  wood (ρo, ρu, ρc, ρui)
  • Determination of wood density
  • Factors which influence wood density
  • Influence of wood density upon mechanical and technological properties

4. Acoustical properties of wood

  • Presentation of acoustical properties
  • Characteristics of resonance wood
  • Factors which influence the acoustical properties of wood

5. Thermal properties of wood

  • Presentation of thermal properties
  • Wood burning
  • Factors which influence the thermal properties of wood

6. Electrical and magnetic properties of wood

  • Wood behaviour in direct-current
  • Wood behaviour in alternating-current
  • Wood behaviour under IR radiation, UV radiation and X-rays
  • Magnetic properties of wood

7. Mechanical and technological properties of wood

  • Types of mechanical stresses
  • Technological properties
  • Factors which influence the mechanical properties of wood

Practical laboratory works with the following topics complete the lecture:

  • Determination of wood moisture content by the oven-dry method
  • Electrical methods for moisture content determination
  • Practical determination of swelling and shrinkage for one softwood and one hardwood
  • Practical determination of the wooden substance density
  • Practical determination of the apparent density of solid wood (ρo and ρu)
  • Practical determination of the tensile, compression, shearing, splitting, bending and torsion strengths
  • Practical determination of wood hardness
  • Practical determination of wear resistance and withdrawal strength
  • Practical determination of acoustical properties of wood
  • Statistical processing of results.

History:
The subject initially entitled „Wood Technology” was taught starting with the year 1948 till 1960 within the “Exploitation and Wood Industry Institute” from Bucharest and the “Silviculture and Wood Processing Institute” from Câmpulung Moldovenesc by Prof dr. eng. Nicolae GHELMEZIU, as head of discipline. Beside a special activity inside the department, Prof Ghelmeziu published numerous handbooks, being the first author of some speciality works, such as: “Wood Technology” in “The Handbook of the Forestry Engineer 84” (Bucharest, 1957) and “Wood Identification” (Bucharest, 1959).

In 1961, two years after the Faculty of Wood Industry was set up within the Polytechnical Institute in Brasov, the subject was taken over by Prof. dr. eng. Jiva FILIPOVICI and was entitled “Wood Science”, a title which was kept for 36 years. Prof. Filipovici stayed as head of discipline until 1972. Within this period, he published the first Romanian reference manual in this field: “Wood Science” Vol I and II (Bucharest 1964, 1965).

Starting with the year 1973 the subject was taken over by Lecturer eng. Petru PESCARUS. He remained as head of discipline for 28 years, being well appreciated by all students who attended the courses of our faculty within this long period. Prof. Pescarus published many reference books, such as: “Wood Science, Vol. I” and the first “Guidebook for practical applications”.

In time, several teachers sustained laboratory hours at this discipline: prof. dr. eng. Gheorghe ZLATE, senior lect. dr. eng. Dietmar Brenndorfer, prof. dr. eng. Maria Cismaru, prof. dr. eng. Aurel Lunguleasa, lect. eng. Mihaela Porojan, lect. eng. Gheorghe BISTRICEANU and others.

Starting with the year 1998, the subject was divided into two parts, the first part being entitled “Wood Anatomy” and the second part being entitled “Physics and Mechanics of Wood”.

In 2001 the subject was taken over by prof.dr.eng. Maria CISMARU who has collaborated with Mr. Petru PESCARUS for 24 years by sustaining laboratory practical works, by performing fundamental research concerning the properties of some exotic species and by contributing to the elaboration of a “Guidebook for practical applications”.

After two years of teaching this subject, Prof.dr.eng. Maria CISMARU published the book ”Physics of wood and wooden materials” (Romanian language) which presents the theoretical basics of each physical property, accompanied by solved numerical applications that are addressed both to faculty students and specialists from wood processing industries.

Present Head of Discipline:
Maria CISMARU, Professor, PhD, graduate of the Faculty of Wood Industry, class 1970.
Title of PhD thesis: “Researches concerning the influence of veneers shrinkage on the shape stability of veneered panels”. Thesis asserted in December 1998 at the “Transilvania” University of Brasov.

Perspectives and Opportunities:
The following development directions are envisaged:

  • Enriching the endowment of the Wood Physics and Mechanics Laboratory with two modern testing machines that will be purchased in frame of a research contract gained by national competition, concerning the quality of wooden material.
  • Accreditation of the Testing Laboratory for Wood and Wooden Products.

 

 
Pagina creata de Costel AGACHE. Intretinere pagina Luminita Brenci. Ultima actualizare, 21 Martie 2008