scholarly journals Determining the conversion factors for selected lengths of medium-sized pine and spruce wood in the S2 group

2018 ◽  
Vol 79 (1) ◽  
pp. 69-76
Author(s):  
Joanna Witkowska ◽  
Krzysztof Jodłowski
Keyword(s):  
Conversion Factor ◽  
Large Range ◽  
Average Diameter ◽  
Raw Material ◽  
Conversion Factors ◽  
Pine Wood ◽  
Technical Requirements ◽  
Spruce Wood ◽  
Round Wood ◽  
General Director

Abstract The aim of the study was to verify the commonly used conversion factors, their realignment and adaptation to current requirements for wood group S2. Our re-evaluation was based on medium-sized pine and spruce wood between 1 m and 3 m long, with an upper diameter of 5 cm to 24 cm without bark. Measurements were carried out on individual raw material pieces (rollers) as well as entire stacks. In total, 1092.026 steres of pine wood and 482.430 steres of spruce wood from five different forest districts were measured. The conversion factors for both pine and spruce were observed to be generally lower than those currently used in PN-D-95000-2002 and the directives of the General Director of State Forests regarding technical requirements on medium-sized round wood. We also confirmed the dependence between the value of the conversion factor and the average diameter of the roller in the stack, although this was not consistently statistically significant due to the influence of a multitude of factors that potentially cancel each other out. The differences of conversion factors obtained for the S2A and S2B groups suggest that more extensive research for pine and spruce wood as well as the development of separate conversion factors is necessary. However, developing appropriate conversion factors for wood of the S2A group (S2AC and S2AP), especially pine wood, will be challenging due to the large range of diameters and curvature permitted by the regulations.

scholarly journals Determination of conversion factors for pine and spruce logs in stacks

2019 ◽  
Vol 80 (3) ◽  
pp. 181-187
Author(s):  
Krzysztof Jodłowski ◽  
Joanna Witkowska
Keyword(s):  
Conversion Factor ◽  
Average Diameter ◽  
Raw Material ◽  
Conversion Factors ◽  
Average Value

AbstractThe aim of this article was to determine the conversion factors for stacked pine and spruce logs with a length of 3–6 m. To this end, we measured stacks and their logs of a total of 3322.12 steres of pine logs and 1468.46 steres of spruce logs. The conversion factors obtained in this work for pine logs of varying lengths negatively correlate with log length. However, statistically significant (p<0.05) differences were only observed between the longest logs as well as logs of 3 and 4 m in length. This may be due to various factors (mainly curvature, the presence of buttresses on butt logs and taper) influencing the stacking process of logs of increasing length. For logs with a length of 3, 4 and 5 m, the average value of the conversion factor increased with the log thickness class, although this dependence was not statistically significant. In the case of spruce raw material, the obtained conversion factors are similar to the values determined in previous studies. There was no significant correlation between the length of the log and its average diameter. A prerequisite for using conversion factors for large-sized logs is accurate stacking, where special attention should be paid to the parallel stacking of individual logs, aligning their front and back sides to be flush and forming the stack so that its top plane is parallel to the ground.

Effect of sawn zone on the quality of lumber in the evaluation of selected pine wood defects

2021 ◽  
Vol 114 ◽  
pp. 26-32
Author(s):  
Marek Wieruszwski ◽  
Radosław Mirski ◽  
Adrian Ttrociński ◽  
Jakub Kawalerczyk
Keyword(s):  
Average Diameter ◽  
General Purpose ◽  
Raw Material ◽  
Pine Wood ◽  
Variable Level ◽  
Structural Applications

Effect of sawn zone on the quality of lumber in the evaluation of selected pine wood defects. In the course of research on the sawn pine raw material with defined distribution of the defects, a variable level of change in the presence of knots was assessed. Initially, the experimental material was classified in terms of the general-purpose timber, and then the strength classes of wood for structural applications were assigned. The proportion of sound knots increased in case of wood obtained from the middle and top zones. In the case of butt-end logs, an increase in the share of the rotten knots having an average diameter of 2-4 cm was observed. The intensity of the defect’s occurrence corresponded with the zone of origin along the large-sized roundwood length.

scholarly journals Experimental tests of PVD AlCrN-coated planer knives on planing Scots pine (Pinus sylvestris L.) under industrial conditions

2021 ◽  
Author(s):  
Krzysztof Nadolny ◽  
Wojciech Kapłonek ◽  
Marzena Sutowska ◽  
Paweł Sutowski ◽  
Piotr Myśliński ◽  
...  
Keyword(s):  
Research Work ◽  
Experimental Tests ◽  
Technical Condition ◽  
Cutting Edge ◽  
Raw Material ◽  
Edge Condition ◽  
Wear Area ◽  
Pine Wood ◽  
Wood Processing ◽  
Machining Operations

AbstractRaw pine wood processing and especially its mechanical processing constitute a significant share among technological operations leading to obtaining a finished product. Stable implementation of machining operations, ensuring long-term repeatable processing results depends on many factors, such as quality and invariability of raw material, technical condition of technological equipment, adopted parameters of work, qualifications and experience of operators, as well as preparation and properties of the machining tools used. It seems that the greatest potential in the search for opportunities to increase the efficiency of machining operations has the modification of machining tools used in it. This paper presents the results of research work aimed at determining how the life of cutting tools used in planing operations of wet pine wood is affected by the application of chromium aluminum nitride (AlCrN) coating to planar industrial planing knives in the process of physical vapour deposition. For this purpose operational tests were carried out under production conditions in a medium-sized wood processing company. The study compares the effective working time, rounding radius, the profile along the knife (size of worn edge displacement, wear area of the cutting edge), selected texture parameters of the planar industrial planing knife rake face and visual analyses of cutting edge condition of AlCrN-coated planar knives and unmodified ones. The obtained experimental results showed the possibility of increasing the life of AlCrN-coated knives up to 154% compared to the results obtained with uncoated ones. The proposed modification of the operational features of the knives does not involve any changes in the technological process of planing, does not require any interference with the machining station nor its parameters, therefore enabling rapid and easy implementation into industrial practice.

scholarly journals The Hungarian Wood-Based Panel Industry and its Impact on the Environment

2016 ◽  
Vol 12 (2) ◽  
pp. 157-172
Author(s):  
Gábor Laborczy ◽  
András Winkler
Keyword(s):  
Carbon Dioxide ◽  
Power Plants ◽  
Negative Impact ◽  
Value Added ◽  
Forest Products ◽  
Air Pollutant ◽  
Raw Material ◽  
Energy Sources ◽  
Forest Products Industry ◽  
Round Wood

Abstract It is well known that worldwide deforestation has a negative impact on the global environment. Forests play an important role in producing oxygen as well as retaining gases that create the greenhouse effect. Forests primarily absorb carbon dioxide, the major air pollutant released by the industrial activities. Energy production is the major source of environmental contamination. In addition to reducing CO2 emissions, another issue this industrial sector must tackle is to decrease the use of fossil fuels by substituting them with renewable, environmentally friendly energy sources. One of the answers to these challenges is the utilization of biomass as energy sources. However, biomass-based fuels include short bolts, split round-wood, pulpwood, bark and by-products of sawmilling, which are the raw materials for the wood-based panel industry as well.Wood utilization of the forest products industry has a major impact on the delayed release of carbon dioxide stored in the wood. All over the world, just as in Hungary, the wood-based panel industry mainly uses low quality wood resources and turns them into value added products. The elongation of the life cycle of low quality wood materials decreases CO2 emissions, thus significantly contributing to environmental protection. Furthermore, it is assumed that raw material demand of the wood-based panel industry could be satisfied by focusing on sustainable forest management and well-planned reforestation. Additionally, special energy-plantations may provide extra wood resources, while waste and other non-usable parts of trees contribute to the effective and economic operation of biomass utilizing power-plants. This paper summarizes the current situation of the Hungarian wood-based panel industry and discusses the effects of the panel manufacturing processes on the environment. Also, it outlines the possible future of this important segment of the forest products industry.

scholarly journals Properties dependence of the lightweight alumina products obtained by a semi-dry pressing method on the alumina type

2020 ◽  
Vol 120 ◽  
pp. 126-133
Author(s):  
V. V. Martynenko ◽  
Yu. A. Krakhmal ◽  
K. I. Kushchenko ◽  
T. G. Tishina
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Raw Materials ◽  
Raw Material ◽  
Pressing Method ◽  
Technical Requirements ◽  
Alumina Grade ◽  
Pitch Coke ◽  
Calcium Hexaluminate ◽  
Dry Pressing

Lightweight materials are widely used in industry for thermal insulation of various thermal units. The choice of lightweight material depends on the specific conditions of service. For the lining of high-temperature units operating in reducing environments, alumina lightweight products are used that contain a minimum amount of Fe2O3 impurities and free (unbound in compounds) SiO2. In JSC “URIR named after A. S. Berezhnoy” a technology of alumina lightweight products of grades KLA-1.1 and KLA-1.3 by a semi-dry pressing method with an application temperature of up to 1550 °C has been developed. These products are made from a mixture of ground and no-milled γ-form alumina of grade 0 and α-form alumina of grade S with additives of pitch coke and chalk. The work purpose was improvement of the alumina lightweight products technology and search for new alternative raw materials along with the currently used alumina grade S. The properties dependence of alumina lightweight products, obtained by the semi-dry pressing method, on the type of alumina α-form, was investigated. As a result of the studies, it was found that, for the manufacture of alumina lightweight products of grades KLA-1.1 and KLA-1.3 by the semi-dry pressing method, alumina grades N and NR can be used as an alternative alumina-containing raw material along with alumina grade S. The phase composition of alumina lightweight products of grades KLA-1.1 and KLA-1.3, which are manufactured using alumina grades S, N and NR, was represented mainly by corundum and calcium hexaluminate. The alumina lightweight products, which were manufactured using alumina grades S, N and NR, were characterized by similar high properties and correspond the technical requirements for grades KLA-1.1 and KLA-1.3.

scholarly journals DIC TEXTURING-ASSISTED ACCELERATED SOLVENT EXTRACTION OF ACTIVE MOLECULES OF POMEGRANATE PEEL

2016 ◽  
Vol 12 (9) ◽  
pp. 4023-4044
Author(s):  
Karim Allaf ◽  
Khaoula Elaydi ◽  
Ibtisam Kamal ◽  
Ahmed Bedoui
Keyword(s):  
Solvent Extraction ◽  
Radical Scavenging ◽  
Effective Diffusivity ◽  
Bioactive Compound ◽  
Average Diameter ◽  
Processing Parameters ◽  
Accelerated Solvent Extraction ◽  
Raw Material ◽  
Phenol Compounds ◽  
Instant Controlled Pressure Drop

The current work discusses the use of Instant Controlled Pressure Drop (DIC) as a pretreatment texturing stage intensifying phenolic compound extraction from South Tunisian Punicagranatum L. peels in both cases of conventional and Accelerated Solvent Extraction (ASE). Response Surface Methodology (RSM) allowed identifying the effects of DIC processing parameters on the yields of Total Phenol Compounds (TPC), Total Flavonoid (TF), Condensed Tannins (CT), and Hydrolysable Tannins (HT), and antioxidant capacities via 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging capacity and ß-carotene-linoleic acid as responses. Comparative methods were used to evaluate DIC-textured and Raw samples. The results obtained confirmed that appropriate DIC-texturing improved both kinetic and yield of bioactive compound extraction using ASE from Punicagranatum L. peels. Extraction kinetics was studied through Coupled Washing-Diffusion CWD model. The effective diffusivity was identified and quantified ranged from 0.27 to 8.22 against 0.4710-10 m2s-1 for DIC textured and raw material (RM), respectively. DIC swelling enabled solid vegetal material matrix to expand and be more adapted to mass transfer thus increasing extractability of the phenol compounds. Scanning Electron Microscope SEM showed that DIC generated pores with an average diameter of 50 µm.

scholarly journals Synthesis and Infrared Performance of SiB6 Powder through “Chemical Oven” Self-Propagating Combustion

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Shuang Shuang ◽  
Fengxia Yang ◽  
Zhiwei Li ◽  
Jiangtao Li ◽  
Xiangmin Meng
Keyword(s):  
Near Infrared ◽  
Integral Intensity ◽  
Synthesis Method ◽  
Average Diameter ◽  
Raw Material ◽  
Infrared Range ◽  
Severe Condition ◽  
Molar Ratios ◽  
Whole Process ◽  
Maximum Reaction

SiB6 powders were prepared by the “chemical oven” method from Si and B powders. Here combustion with acid pickling “two-step” mode replaces the traditional synthesis method which helps to avoid severe condition of high temperature and high pressure. It could realize maximum reaction temperature to about 2000°C, and the whole process just needs ∼30 s. The average diameter of products is ∼10 μm. And the raw material Si and B are ∼3 μm and ∼20 μm, respectively. The infrared emissivity of products was evaluated by UV-vis spectrum with absorption band around 250∼2500 nm. All five samples show higher emissivity over UV-visible light range with lower emissivity over near-infrared range. Typically, the sample’s Si/B ratio of 1 : 1 shows highest integral intensity for about 0.85 compared with other molar ratios. It can be used as a more simple and effective method to obtain infrared ceramic SiB6 with high emissivity.

Capability, social capital and opportunity-driven graduate entrepreneurship in Tanzania

2018 ◽  
Vol 25 (4) ◽  
pp. 554-572 ◽  
Author(s):  
Ingrid Wakkee ◽  
Karel Hoestenberghe ◽  
Ernest Mwasalwiba
Keyword(s):  
Social Capital ◽  
Conversion Factor ◽  
Policy Makers ◽  
Conversion Factors ◽  
Content Type ◽  
Ability To Act ◽  
Cultural Systems ◽  
Career Option ◽  
New Graduate ◽  
Critical Conversion

Purpose The purpose of this paper is to gain insight into the reasons why most Tanzanian graduates do not consider entrepreneurship as an attractive career option despite dire labor market conditions, while a small number of them are able to benefit from local opportunities. Design/methodology/approach Utilizing insights from capability and social capital perspectives, a qualitative investigation based on interviews, group discussions and document analysis was undertaken to explore how this phenomenon can be explained and remedied. Findings This study shows that many graduates value entrepreneurship as a potential career but many find their way to be act upon these aspirations blocked. Indeed, actual entrepreneurial capability is only available to a minority of graduates with access to powerful connections who are able to benefit from technological and financial conversion factors. Most graduates cannot benefit from these conversion factors due to the lack of the necessary social capital to break through to the legal, tax, financial and cultural systems. Hence, the authors argue that social capital itself is actually a critical conversion factor toward developing entrepreneurial capability. Research limitations/implications The insight formulated in this study are based on a qualitative analysis of the Tanzanian context and formulated specifically for this particular context. At the same time, the country shares many characteristics with other countries in Africa, many of which are struggling to move toward a more entrepreneurial society. Hence, the recommendations may partially be transferable beyond the specific Tanzanian situation. Theoretically, the notion that social capital should be considered as a key conversion factor enabling aspiring entrepreneurs in translating valued functionings into actualized functionings and thus toward enhancing entrepreneurial capability opens up novel avenues for empirical research into how entrepreneurship can be stimulated. Social implications This study searches for conversion factors from the actual “functioning” toward the real “capability” allowing to succeed as a new graduate and find that social capital itself might act as the critical conversion factor. That brings the authors to the recommendations for policy makers, educators and media, argued in such a way that the entrepreneurial capability of young graduates and their ability to tap into relevant social capital can be enhanced. Originality/value The combination and integration of the Sen’s capability approach with social capital perspectives offers a novel way to explain difference in responses to the Tanzanian institutions and their ability to act upon a valued functioning such as opportunity-driven entrepreneurship.

Analysis of the influence of larch fibers and particles on selected properties of fiber- and particleboards

2020 ◽  
Vol 111 ◽  
pp. 43-52
Author(s):  
Bartłomiej Pazio ◽  
Piotr Boruszewski
Keyword(s):  
Cross Section ◽  
Density Profile ◽  
Internal Bond ◽  
The Other ◽  
Raw Material ◽  
Modulus Of Rupture ◽  
Thickness Swelling ◽  
European Larch ◽  
Pine Wood ◽  
Larch Wood

Analysis of the influence of larch fibers and particles on selected properties of fiber- and particleboards. The paper presents the results of the research on the effect of the addition of fibers and particles obtained from European larch wood (Larix decidua Mill) from plantations on selected properties of fiber- and particleboards in comparison to the boards of the same structure based on typical industrial raw material (pine wood) uses by European wood based panels industry. The differences were shown in the tests, i.e.: modulus of rupture (MOR), modulus of elasticity in static bending (MOE), internal bond (IB), thickness swelling after 2 and 24 hours soaking in water and density profile. In the MOR and MOE tests, larch boards with a minimum 50% fiber share were characterized by comparable values of the properties determined to pine boards, while in the other variants, boards made of pine wood had better properties. In most cases, the larch boards were characterized by significantly lower values of swelling by thickness (with the exception of boards made of fibers) than boards made of wood from forest cultivation. The density profile of the boards on the cross-section of the plantation raw material did not differ from the boards made of pine raw material.

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