Detection of fungal decay by high-energy multiple impact (HEMI) testing

Holzforschung ◽  
2006 ◽  
Vol 60 (2) ◽  
pp. 217-222 ◽  
Author(s):  
Christian Brischke ◽  
Christian Robert Welzbacher ◽  
Andreas Otto Rapp
Keyword(s):  
Structural Changes ◽  
Brown Rot ◽  
High Energy ◽  
White Rot ◽  
Fungal Decay ◽  
Highly Correlated ◽  
Thermally Modified Wood ◽  
Impact Milling ◽  
Multiple Impact ◽  
Steel Balls

Abstract The suitability of a previously described high-energy multiple impact (HEMI) test for the detection of early fungal decay was examined. The HEMI test characterises the treatment severity of thermally modified wood by stressing the treated material by thousands of impacts of pounding steel balls. This method differentiates between heat treatment intensities, which are manifest as structural changes in the wood. Similar changes in wood structure are known for wood decayed by fungi. Pine (Pinus sylvestris L.) decayed by brown rot and beech (Fagus sylvatica L.) decayed by white rot were tested. Mass loss caused by fungal decay and resistance to impact milling (RIM) determined in HEMI tests were found to be highly correlated. Testing of non-degraded pine, beech, and ash (Fraxinus exelsior L.) showed only marginal effects of wood density on RIM. Furthermore, annual ring angles and RIM of spruce (Picea abies Karst.) were not correlated. Accordingly, the detection of RIM reduction in decayed wood is not masked by variations in density and orientation of the annual rings. Previous results showed no adverse effects of weathering on RIM. Thus, the detection of fungal decay with HEMI tests is feasible not only for laboratory purposes, but also for wood in outdoor applications that has already undergone weathering.

scholarly journals Synthesis of the Mg2Ni Alloy Prepared by Mechanical Alloying Using a High Energy Ball Mill

2019 ◽  
Vol 54 (1) ◽  
Author(s):  
José Luis Iturbe-García ◽  
Manolo Rodrigo García-Núñez ◽  
Beatriz Eugenia López-Muñoz
Keyword(s):  
Mechanical Alloying ◽  
Ball Mill ◽  
Structural Changes ◽  
Weight Ratio ◽  
Structural Evolution ◽  
High Energy ◽  
Process Time ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
Steel Balls

Mg2Ni was synthesized by a solid state reaction from the constituent elemental powder mixtures via mechanical alloying. The mixture was ball milled for 10 h at room temperature in an argon atmosphere. The high energy ball mill used here was fabricated at ININ. A hardened steel vial and three steel balls of 12.7 mm in diameter were used for milling. The ball to powder weight ratio was 10:1. A small amount of powder was removed at regular intervals to monitor the structural changes. All the steps were performed in a little lucite glove box under argon gas, this glove box was also constructed in our Institute. The structural evolution during milling was characterized by X-ray diffraction and scanning electron microscopy techniques. The hydrogen reaction was carried out in a micro-reactor under controlledconditions of pressure and temperature. The hydrogen storage properties of mechanically milled powders were evaluated by using a TGA system. Although homogeneous refining and alloying take place efficiently by repeated forging, the process time can be reduced to one fiftieth of the time necessary for conventional mechanical milling and attrition.        

Interrelationship between the severity of heat treatments and sieve fractions after impact ball milling: a mechanical test for quality control of thermally modified wood

Holzforschung ◽  
2006 ◽  
Vol 60 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Andreas Otto Rapp ◽  
Christian Brischke ◽  
Christian Robert Welzbacher
Keyword(s):  
Mechanical Test ◽  
Robinia Pseudoacacia ◽  
Abies Alba ◽  
Dynamic Strength ◽  
High Energy ◽  
Strength Properties ◽  
Test Method ◽  
Specimen Preparation ◽  
Impact Milling ◽  
Steel Balls

Abstract Thermal modification processes improve the durability and dimensional stability of wood, but strength properties, especially dynamic ones, are compromised. Results from standard dynamic strength testing, such as impact bending tests, suffer from high variability and therefore require a high number of replicates. To overcome this, a new test method named high-energy multiple impact (HEMI) was developed by investigating heat-treated Picea abies Karst., Abies alba Mill. and untreated Robinia pseudoacacia L. The method is based on crushing small specimens by thousands of impacts from pounding steel balls in a heavy vibratory mill. The level of destruction was determined by sieving and analyzing the size distribution of the fragments. We calculated the resistance to impact milling (RIM) based on the mass of the size fractions. RIM shows a linear correlation with the intensity of the thermal treatment. The HEMI test method has the following advantages: small number of specimens, short time for specimen preparation, small variances, and high reproducibility of results.

Effect of Mechanochemical Activation on Surface Oxidation of Steel Ball in Milling Serpentinite

2005 ◽  
Author(s):  
He Yang ◽  
Shenghua Li ◽  
Yuansheng Jin
Keyword(s):  
Structural Changes ◽  
Surface Oxidation ◽  
High Energy ◽  
Steel Ball ◽  
Chemical States ◽  
Time Variations ◽  
Shearing Strain ◽  
Tribochemical Activation ◽  
Steel Balls ◽  
Main Component

Serpentinite is the main component of the worn metal reconditioner formulation chemistry and is supposed to be functioning by converting, under shearing strain forces, into oxygen-releasing species through mechanochemical / tribochemical activation and relaxation. Research in this effort employed a high energy planetary ball mill to conduct simulation experiments for understanding the mechanically activated oxidation of GCr15 steel ball surfaces in the course of milling the serpentinite powders in sealed steel containers at room temperatures. As a function of milling time, variations of chemical states of the milled ball surfaces were characterized with SEM, EDX and XPS. Examinations evidenced that plastic deformed layers emerged on the working surfaces of the milled steel balls. Analyses of the milled serpentinite powders were correlated to observations of the chemical and structural changes on the working surfaces of the milled steel balls. Role of the milled serpentinite powder in stimulating the mechanochemical oxidation of the working surfaces of steel balls was briefly expounded.

Changes in sorption and electrical properties of wood caused by fungal decay

Holzforschung ◽  
2019 ◽  
Vol 73 (5) ◽  
pp. 445-455 ◽  
Author(s):  
Christian Brischke ◽  
Simon Stricker ◽  
Linda Meyer-Veltrup ◽  
Lukas Emmerich
Keyword(s):  
Beech Wood ◽  
Sorption Isotherms ◽  
Brown Rot ◽  
European Beech ◽  
White Rot ◽  
White Rot Fungus ◽  
Decayed Wood ◽  
Vapor Sorption ◽  
Fungal Decay ◽  
Dynamic Vapor Sorption

Abstract As wet wood is prone to degradation by wood-destroying fungi, the monitoring of the moisture content (MC) of wood can be used to quantify the risk of fungal infestation. Fungal decay alters the sorption and electrical conductivity of wood, and thus the goal of the present study was to measure the electrical resistance (R) of wood after fungal decay as a function of MC. Scots pine sapwood (Pinus sylvestris L.) and European beech wood (Fagus sylvatica L.) were submitted to decay by Coniophora puteana (a brown rot fungus, BR) and Trametes versicolor (a white rot fungus, WR) and the mass loss (ML) due to the fungal metabolism was measured. The sorption isotherms were determined by dynamic vapor sorption (DVS), and comparative gravimetric- and R-based MC measurements were conducted. BR and WR reduced the sorption of wood and lowered its R in the hygroscopic range, where the decay led to an overestimation of wood MC, while wood MC was dramatically underestimated above fiber saturation (FS). Specimens showed an MC well above FS if measured directly after harvesting and an increased R compared to undecayed wood at a given MC. BR-decayed specimens were dried and rewetted, and such specimens showed an elevated R beyond FS. In the case of WR-decayed wood, the R was reduced at a given MC.

scholarly journals Changes in microstructure and stiffness of Scots pine (Pinus sylvestris L) sapwood degraded by Gloeophyllum trabeum and Trametes versicolor – Part II: Anisotropic stiffness properties

Holzforschung ◽  
2012 ◽  
Vol 66 (2) ◽  
Author(s):  
Thomas K. Bader ◽  
Karin Hofstetter ◽  
Gry Alfredsen ◽  
Susanne Bollmus
Keyword(s):  
Mechanical Properties ◽  
Pinus Sylvestris ◽  
Scots Pine ◽  
Trametes Versicolor ◽  
Brown Rot ◽  
White Rot ◽  
Cellulose Microfibrils ◽  
Gloeophyllum Trabeum ◽  
Fungal Decay ◽  
Tangential Stiffness

Abstract Fungal decay considerably affects the macroscopic mechanical properties of wood as a result of modifications and degradations in its microscopic structure. While effects on mechanical properties related to the stem direction are fairly well understood, effects on radial and tangential directions (transverse properties) are less well investigated. In the present study, changes of longitudinal elastic moduli and stiffness data in all anatomical directions of Scots pine (Pinus sylvestris) sapwood which was degraded by Gloeophyllum trabeum (brown rot) and Trametes versicolor (white rot) for up to 28 weeks have been investigated. Transverse properties were found to be much more deteriorated than the longitudinal ones. This is because of the degradation of the polymer matrix between the cellulose microfibrils, which has a strong effect on transverse stiffness. Longitudinal stiffness, on the other hand, is mainly governed by cellulose microfibrils, which are more stable agains fungal decay. G. trabeum (more active in earlywood) strongly weakens radial stiffness, whereas T. versicolor (more active in latewood) strongly reduces tangential stiffness. The data in terms of radial and tangential stiffnesses, as well as the corresponding anisotropy ratios, seem to be suitable as durability indicators of wood and even allow conclusions to be made on the degradation mechanisms of fungi.

Investigation of fungal decay of poplar wood treated with pistachio resin

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 779-788
Author(s):  
Maede Ahadnezhad ◽  
Soheila Izadyar ◽  
Davood Efhamisisi
Keyword(s):  
Mass Loss ◽  
Trametes Versicolor ◽  
Populus Deltoides ◽  
Treated Wood ◽  
Brown Rot ◽  
White Rot ◽  
White Rot Fungus ◽  
Poplar Wood ◽  
Fungal Decay ◽  
Brown Rot Fungus

The density, swelling, and fungal decay of poplar (Populus deltoides) wood treated with pistachio resin (PR) obtained from Pistacia atlantica were investigated. The white-rot fungus Trametes versicolor and the brown-rot fungus Coniophora puteana were used. Methanolic solutions of PR with different concentrations of 1%, 6%, 12%, and 15% were used as the preservative solution. Wood samples were saturated by two different vacuum/pressure (V/P) and dipping methods. The density, volumetric swelling of treated wood, and their mass loss (ML) caused by fungal decay were determined. The density of treated species increased to 15.4% and 5.8% for V/P and dipping methods, respectively, at 15% PR concentration. The volumetric swelling of the treated samples was reduced to 24.5% and 16.8% for V/P and dipping procedure, respectively, at 15% PR concentration. The mass loss of treated samples after exposure to T. versicolor was less than the untreated one (17.4% for V/P and 22.6% for dipping methods at 15% PR concentration). The results showed the better performance of V/P treatment in promotion of wood durability against fungal decay than the dipping method.

scholarly journals The Impact of Anatomical Characteristics on the Structural Integrity of Wood

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 199 ◽  
Author(s):  
Lukas Emmerich ◽  
Georg Wülfing ◽  
Christian Brischke
Keyword(s):  
Structural Integrity ◽  
Growth Ring ◽  
High Energy ◽  
Anatomical Characteristics ◽  
Hardwood Species ◽  
Wide Range ◽  
Ray Density ◽  
Impact Milling ◽  
Multiple Impact ◽  
The Impact

The structural integrity of wood is closely related to its brittleness and thus to its suitability for numerous applications where dynamic loads, wear and abrasion occur. The structural integrity of wood is only vaguely correlated with its density, but affected by different chemical, physico-structural and anatomical characteristics, which are difficult to encompass as a whole. This study aimed to analyze the results from High-Energy Multiple Impact (HEMI) tests of a wide range of softwood and hardwood species with an average oven-dry wood density in a range between 0.25 and 0.99 g/cm³ and multifaceted anatomical features. Therefore, small clear specimens from a total of 40 different soft- and hardwood species were crushed in a heavy vibratory ball mill. The obtained particles were fractionated and used to calculate the ‘Resistance to Impact Milling (RIM)’ as a measure of the wood structural integrity. The differences in structural integrity and thus in brittleness were predominantly affected by anatomical characteristics. The size, density and distribution of vessels as well as the ray density of wood were found to have a significant impact on the structural integrity of hardwoods. The structural integrity of softwood was rather affected by the number of growth ring borders and the occurrence of resin canals. The density affected the Resistance to Impact Milling (RIM) of neither the softwoods nor the hardwoods.

Effects of extractives on mechanical properties and durability of rubberwood-HDPE composites

Holzforschung ◽  
2020 ◽  
Vol 74 (11) ◽  
pp. 1061-1070
Author(s):  
Zilun Wang ◽  
Chuanshuang Hu ◽  
Jin Gu ◽  
Banyat Cherdchim ◽  
Dengyun Tu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Brown Rot ◽  
Decay Resistance ◽  
Deionized Water ◽  
White Rot ◽  
Fungal Decay ◽  
Plastic Composites ◽  
Surface Topographies ◽  
Positive Effect ◽  
Scanning Electron

AbstractIn this study, the effects of rubberwood extractives on the mechanical properties and fungal decay resistance of rubberwood-based wood plastic composites (WPCs) were explored. Three different solvents, benzene-ethanol, methanol, and deionized water, were used to remove the extractives of the rubberwood flour (RWF). The surface topographies of the prepared rubberwood-based WPC and the rubberwood itself were characterized using digital instruments and scanning electron microscopy (SEM). The results indicate that the mechanical properties of the WPC prepared using extracted RWF were higher than those of the WPC prepared with unextracted RWF. The sequences of resistance to the growth of mold on the surface of the WPC were ranked as follows: deionized-water-extracted WPC > methanol-extracted WPC > benzene-ethanol-extracted WPC > unextracted WPC. The WPC made with extracted RWF had better brown-rot resistance and worse white-rot resistance than the unextracted WPC. These results demonstrate that the removal of rubberwood extractives has a positive effect on the mechanical properties and mold and fungal decay resistance of rubberwood-based WPCs.

Revalorizing Lignocellulose for the Production of Natural Pharmaceuticals and Other High Value Bioproducts

2019 ◽  
Vol 26 (14) ◽  
pp. 2475-2484 ◽  
Author(s):  
Congqiang Zhang ◽  
Heng-Phon Too
Keyword(s):  
Clostridium Thermocellum ◽  
White Rot Fungi ◽  
Brown Rot ◽  
Cost Effective ◽  
White Rot ◽  
Chemical Pretreatment ◽  
Significant Challenge ◽  
Drug Molecules ◽  
Natural Medicine ◽  
Renewable Natural Resource

Lignocellulose is the most abundant renewable natural resource on earth and has been successfully used for the production of biofuels. A significant challenge is to develop cost-effective, environmentally friendly and efficient processes for the conversion of lignocellulose materials into suitable substrates for biotransformation. A number of approaches have been explored to convert lignocellulose into sugars, e.g. combining chemical pretreatment and enzymatic hydrolysis. In nature, there are organisms that can transform the complex lignocellulose efficiently, such as wood-degrading fungi (brown rot and white rot fungi), bacteria (e.g. Clostridium thermocellum), arthropods (e.g. termite) and certain animals (e.g. ruminant). Here, we highlight recent case studies of the natural degraders and the mechanisms involved, providing new utilities in biotechnology. The sugars produced from such biotransformations can be used in metabolic engineering and synthetic biology for the complete biosynthesis of natural medicine. The unique opportunities in using lignocellulose directly to produce natural drug molecules with either using mushroom and/or ‘industrial workhorse’ organisms (Escherichia coli and Saccharomyces cerevisiae) will be discussed.

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