Changes of ashwood pH-value during conventional dryingAleš Straže
, Sandi Torkar
, Vesna Tišler
, Željko Gorišek
Povzetek: Changes of pH of sawn wood during conventional drying were studied. Green ashwood boards (Fraxinus excelsior L.), 25.4 mm in thickness, were exposed to 1 month air drying and to kiln drying using 7 schedules, reached by varying temperature (20°C, 30°C and 65°C) and relative air humidity (33% to 90%). Wood samples for pH and moisture content (MC) determination were taken in successive time interval at 3 board`s depths (1/10, 1/3 and 1/2 of thickness).MC was established gravimetrically. pH-value determination of solid wood water system by suspending wood dust into distilled water was used. The lowest used temperature and duration of drying procedure had not significant influence on wood pH. Wood acidification was confirmed at higher drying temperatures (30°C and 65°C), particularly with lower drying rates and prolongation of the procedure. Among all the factors, drying temperature had the greatest impact on the pH-value of wood.
Ključne besede: ash-wood, pH-value, drying, drying conditions
DiRROS - Objavljeno: 12.07.2017; Ogledov: 2517; Prenosov: 947
Celotno besedilo (279,40 KB)
The impact of business informatics develpoment on business operations in Slovenian wood industry companiesJože Kropivšek
, Leon Oblak
Povzetek: The rapid development of business informatics is greatly influencing (global) business environment formation, while informatisation of business has, at the same time, a significant impact on assuring adapted business operations due tothis (changeable) environment. Informatics is closely connected with almost every (business) field in companies. Thus, the theoretical analysis in the article shows business (and production) informatics course of development and its impact on business operations in (also) Slovenian wood industry companies.A practical analysis in those companies was made with the aid of theopinion pool method in the years 2000 in 2003. The major deficiencies were established first of all in the (contentual) coverage of business processes bythe information system. However, information technology in these companies seems to be relatively up-to-date. According to those (established) deficiencies, possible solutions were indicated to solve the current situationin Slovenian wood industry companies, which was one of the main objectives of the performed research.
Ključne besede: poslovna informatika, poslovni informacijski sistemi, lesnoindustrijsko podjetje, Slovenija, business informatics, business information systems, wood industry firms, Slovenia
DiRROS - Objavljeno: 12.07.2017; Ogledov: 2693; Prenosov: 976
Celotno besedilo (281,08 KB)
Suggested approach to the financial controlling in wood enterprisesMariana Sedliačikova
, Denis Jelačić
, Josef Drábek
, Leon Oblak
Povzetek: The aim of this paper is to analyse theoretical and practical approaches to the fundamentals, place, roles, functions and contents of the financial controlling in wood enterprises. After analysing various works by domestic andforeign authors, we designed our own approach to the problem of financial controlling, which is integrated into the subsystem of operative controlling and emphasises the relations between single subsystems of controlling. Financial controlling is a relatively independent part of enterprise controlling, whose main objective is to provide for liquidity in a company at all times and to ensure that the prime target of profitability is achieved at the same time.
Ključne besede: wood enterprise, financial controlling, management, financial stability
DiRROS - Objavljeno: 12.07.2017; Ogledov: 2551; Prenosov: 889
Celotno besedilo (653,94 KB)
Launching work orders into production of wood enterprise with the multi-criteria decision-making methodLeon Oblak
, Boštjan Novak
, Igor Lipušček
, Jože Kropivšek
Povzetek: Quality information is crucial for planning and running of production in wood industry companies. Information of crucial importance is the following: quality in the production process according to work orders and types of product, the information on the missing materials i.e. constituent parts according to projects i.e. work orders and the information on launching work orders into production. The method of multi-criteria decision-making was used for determining the order of launching group products into production. We studied three main criteria: market factors, organisation-production factors and economic factors. For computer support, we chose the computer programme DEXi, which represents the framework of the expert system for multi-criteria decision-making.
Ključne besede: wood enterprise, work orders, organization, multi-criteria decision-making method
DiRROS - Objavljeno: 12.07.2017; Ogledov: 2554; Prenosov: 965
Celotno besedilo (648,58 KB)
Densification of woodAndreja Kutnar
, Milan Šernek
Povzetek: The paper treats the processes involved in wood densification and provides a summary of the state-of-the-art, as presented in the literature, with regard to densification as achieved by compression, accompanied by some form of hydrothermal treatment. The viscoelastic nature of wood is discussed, togetherwith its thermal softening and typical stress-strain relationships. The properties of densified wood products depend, apart from processing parameters, on various anatomical features such as density, the percentage of late wood material, ray volume and the loading direction. The problems associated with wood stabilization after densification are also treated. Relevant examples of wood densification from fundamental research, and the results of applied studies significant for everyday practice, are presented. Aspecial focus is given on the process of viscoelastic thermal compression (VTC) of wood.
Ključne besede: wood, densification, softening, transverse compression, viscoelasticity, glass transition temperature
DiRROS - Objavljeno: 12.07.2017; Ogledov: 2459; Prenosov: 967
Celotno besedilo (476,08 KB)
Organisational model of a globally oriented wood industry companyJože Kropivšek
, Rudi Rozman
Povzetek: The paper provides an answer to the question as to in what way and with which organizational steps a wood industry company can be (more) adaptable and successful in a rapidly changing (global) business environment. The purpose ofthe article is to form an organizational model of a globally oriented wood industry company, considering the three required model properties: repeatability, efficiency and productiveness, as well as practical applicability. Research is limited to actual state in Slovenian wood industry practice with some specifics that should be considered by other implications of the research. Practical applicability of the model is based on these findings and is ensured by making guidelines on the basis of which companies can organise their businesses. These guidelines include suggested measures forindividual areas of business organization with the intention of increasing adaptability and innovativeness of business operation, improving competitive ability, and the ability of constant improvement. The paper provides a new organizational approach, specialized for making wood industry companies successful in the changing business environment.
Ključne besede: adaptability, globalisation, model, organization, wood industry company
DiRROS - Objavljeno: 12.07.2017; Ogledov: 2460; Prenosov: 978
Celotno besedilo (474,46 KB)
Inclusion of consumers in the forming of wood fuel trade market on the pattern of questionnaired householdsBenjamin Leskovec
, Iztok Winkler
Povzetek: The research of wood fuel trade is market management oriented at household level. We devoted our attention to determine the key questions, market segmentation and market potentials. 909 households, which took part in the questionnaire and received financial support to purchase a wood biomass boilerfrom 2003 until 2006, represented our data source. The analysed pattern of questionnaired households indicates a vast unrealized developmental potential at placing additional quantities of chunkwood and forest chips on the market. Own forests still represent the most important heating source in households. Switching to wood biomass heating is practiced particularly by fuel oil consumers. Since the consumer has been placed into the centre of our research, we present some fundamental findings on product making and product development, its price, sale, promotion and management control. Our findings indicate that right business decisions and the ability to adjust to the marketfluctuation enable us good developmental possibilities.
Ključne besede: wood biomass, wood fuel trade, households, market management, chunkwood, forest chips, pellets, Slovenia
DiRROS - Objavljeno: 12.07.2017; Ogledov: 2568; Prenosov: 983
Celotno besedilo (515,49 KB)
Internal and external moisture transport resistance during non-stationary adsorption of moisture into woodBojan Bučar
Povzetek: The assumption that non-stationary sorption processes associated with wood canbe evaluated by analysis of their transient system response to the disturbance developed is undoubtedly correct. In general it is, in fact, possible to obtain by time analysis of the transient phenomenon - involving the transition into an arbitrary new state of equilibrium - all data required for a credible evaluation of the observed system. Evaluation of moisture movement during drying or moistening requires determination of external moisture transfer resistance from or to wood surfaces, as well as internal resistance. Time-dependent changes in the moisture content of the spruce (Picea abies Karst.) samples of different thickness were monitored gravimetrically, during which the frequency of weighing was in accord with thespeed of moistening. It was assumed that quasi-isothermal sorption processes associated with wood could be evaluated as first order systems. The characteristic time constant ? determines, wholly and uniformly, the time dependence of the sorption process for the relevant sorption range of wood tissue. The connection between the time constant and the thickness of the sample measured in the direction of the material flux is potential, with the power depending solely on the relationship between the external mass transfer convection and internal diffusion resistance. To determine the said resistances or coefficients of mass transfer convection and diffusivity, the experiment must be carried out on samples of varying thickness. It is only in this way that the external mass transfer convection and internal diffusion resistance can be correctly distinguished.
Ključne besede: wood sorption, first order system, time constant, mass transfer, diffusivity
DiRROS - Objavljeno: 12.07.2017; Ogledov: 2574; Prenosov: 944
Celotno besedilo (428,03 KB)
Assessing maximum loads when skidding wood uphill with tractorsBoštjan Košir
, Jurij Marenče
Povzetek: The results of measuring maximum loads on different slopes when skidding uphill with WOO DY 110 cable skidder and adapted 4WD agricultural tractor AGT 835 are described in the article. Both tractors are very different and were chosen for the purpose of finding the limits of uphill skidding. Besides the slope, the pre-designated loads of different sizes and log orientation (butt-end or top-end forward) have been main variables. The trial was conducted on two concave shaped test skid trails in the forest. On the lower altitudes, the skid trails had small inclination, which slowly increased to 42% on the track where WOODY 110 was tested, and 27% where AGT 835 was measured. First the loads were skidded uphill with butt-end and then with top-end forward. The purpose was to choose too heavy loads, as we wished to stop tractors due to overload, but on different slopes. The proper load formation (butt-end forward if possible) in uphill skidding is most important on steeper skid trails. The dependency between maximum load and slope is linear. The calculated theoretical maximum load on horizontal surface enables us to make similar assessment for any other tractor weighing between 2 and 7 tons. For this purpose, John Deere 6220 and LIMB 80 LUXS adapted agricultural tractors for forest use were chosen and compared. The ratio between the tractor load on different slopes and tractor weight was calculated for all four tractors included in our comparison. Apart from the weight, tractor's engine torque (power) has the decisive influence on the load size. Maximum loads on different slope categories were calculated according to different engine powers.
Ključne besede: tractor, skidding wood, maximum slope, maximum load
DiRROS - Objavljeno: 12.07.2017; Ogledov: 2556; Prenosov: 852
Celotno besedilo (1,19 MB)
Effect of temperature on the eradication of house longhorn beetle larvae in wood by microwave treatmentFranc Pohleven
, Martin Klinc
Povzetek: In repressive protection of cultural/historical woodwork, microwaves have many advantages over conventional heating. The research%s objective was to examine conditions for eradication of house longhorn beetle larvae (Hylotrupes bajulus) in spruce wood (Picea abies) using microwaves. Larvae, inserted at different depths of spruce blocks containing 12% and 42% of moisture, were exposed to microwaves. Two apparatuses were used; a 750W commercial microwave chamber and a newly developed horn antenna microwave device with the power of 800W and a frequency of 2.45GHz, for targeted radiation. We discovered that the inner part of wood warmed up quicker than the surface heated to 65°C. For successful suppression larvae in the wood need to be heated to 54.5°C, for 10 seconds. The necessary exposure time increases with increasing thickness of wood. The surface of wood containing more moisture is heated quicker, but increased moisture slows down the penetration of microwaves into the wood specimen. Therefore, larvae in wood of lower moisture (12%) died faster, both those 20mm under surface (1.5min) and those at 130 mm of depth (10.5min).
Ključne besede: wooden objects, repressive wood protection, microwaves, heating, wood moisture content, house longhorn beetle, Hylotrupes bajulus
DiRROS - Objavljeno: 25.10.2017; Ogledov: 3038; Prenosov: 1573
Celotno besedilo (1,52 MB)