Volume 14 Issue 4

Physical proprieties of particleboard, medium-density fiberboard, and wood-plastic composite board were studied by measuring the thickness and weight changes during repeated humidity cycling (RHC). The thickness stability, moisture absorbing capacity, and internal band strength of the control and treated specimens were measured for the three tested materials. The wood-plastic composite board showed the greatest stability, with only small changes in thickness and weight. Temperature is a key component of RHC treatment, with greater thickness changes after six cycles at 50 °C than after nine cycles at 20 °C. Compared with the control materials, the thickness stability of RHC-treated materials was decreased by 23.7 to 31.8%; RHC decreased the internal bond strength of specimens 22 to 23% for particleboard and medium-density fiberboard and 2.15% for wood-plastic composite board. Overall, thickness stability and internal bonding strength of the tested materials were highly correlated.

The aim of this work was to investigate the possibility of processing forest residues by chemical delignification preceded by mild steam explosion. The focus was on using soda pulping, due to its simplicity. Kraft cooking was used for comparison to improve the understanding of the separation of the complex yet promising resource. The raw material consisted of chipped branches, bark, and twigs of mixed hardwood and softwood. Analysis of the raw material proved to be challenging due to the presence of a substantial fraction of extractives. Analysis of the pulps showed that the forest residue delignification was faster than that of wood. The effects of steam explosion were evaluated with the help of composition analysis, gel permeation chromatography (GPC) for the molecular weight of lignin, and NMR for the changes in its structure. The impact of steam explosion was found to be limited, possibly due to the relatively small size of the material.

Lumber mills generate a huge volume of residues, with tree bark and saw shavings being main contributors. A small amount of this material is burned for energy generation, though most of it is left on the sawmill grounds or dumped in sanitary landfills, thus presenting a huge environmental issue. This study deals with the application of eucalyptus bark and saw shavings for the manufacturing of oriented strand board (OSB). Four types of panel compositions where studied: 25%, 50%, 75%, and 90% of bark content; 10% percent of shavings for all of them, and a variable content of pine strands. The adhesive was phenol formaldehyde at 6% related to the dry mass of the components. Because an important characteristic of OSB panels is their response to swelling, a 1% of paraffin emulsion was added to seal the particles. The results showed that only the 90%-bark panel could meet OSB standard prescriptions as a type 1 “dry environment application”.

Spindleless lathes have shown great potential for the efficient conversion of small native forest logs in Australia. However, a major impediment to the further commercial adoption of this processing approach for native forest small-diameter logs is the absence of reliable and available data on the quantities of logs possibly available and suitable for this purpose. This study undertaken in hardwood and white cypress pine (Callitris glaucophylla) native forests and at sawmills in Queensland, Australia, demonstrated that there are potentially substantial quantities (up to 10.5 m3 per hectare of Crown native hardwood, 14 m3 per hectare of private forest hardwood and 75,000 m3 per year of Crown white cypress pine) logs suitable for spindleless lathe rotary veneer processing. However, access to and utilization of these logs will depend on many factors including accommodating Government policies and log supply agreements; potential alterations in the code of practice for native forest harvesting, silviculture, tree marking and sales practices; diversion of logs from other uses; and development of appropriate log specifications.

In recent years, medium density fiberboard has been extensively used for furniture production. Often it is painted or coated using a PVC film in modern production, after the surfaces are formed via CNC machining. The surface roughness of medium density fiberboard used in this way is very important for the quality of the surface. In previous studies, the effects of the cutting parameters of a CNC router on the surface roughness of medium density fiberboard were investigated using laboratory test samples. The present study focused on the effects of certain cutting parameters of a CNC router on the surface roughness of real size test samples. In addition, the energy consumption and total processing time of the CNC router were investigated, in relation to the cutting parameters. Three different spindle speeds (8000 rpm, 12,000 rpm, and 16,000 rpm) and feed rates (3 m/min, 5 m/min, and 7 m/min) were used. According to the data obtained, it was determined that as the spindle speed increased, the surface roughness decreased, and the total energy consumption increased. However, as the feed rate increased, the surface roughness increased, and the total energy consumption decreased.

A comprehensive investigation was undertaken of red–black lacquer films excavated from a tomb in the Qin and Han Dynasty period (221 BC to AD 8). Cross-sectional observation was conducted via metallomicroscopy and field-emission scanning electron microscopy (FE-SEM). Morphological characteristics were investigated via FE-SEM with energy dispersive X-ray spectrometry (EDX). X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy were also conducted. The results of the cross-sectional analysis showed that the finished lacquer films on the wood body included a ground layer with coarse materials and a lacquer layer with delicate materials. Both SEM and EDX indicated that carbon black was used as the main black pigment, and cinnabar was used as the main red pigment. Compared with the standard card test, the XRD patterns of the Chinese lacquer were similar to that of quartz (SiO2), indicating that SiO2 was used as a putty powder during lacquer finishing. Compared with the FTIR spectrum of the fresh lacquer film, only a small amount of free carbonyl was found in the degraded lacquer, and some organosilicates were likely generated during degradation spanning thousands of years.

A new algal-bacterial granular sludge treatment method was used to treat salty eutrophication water. The results indicated that the treatment removed more than 98% of the total inorganic nitrogen and the total phosphorus after a 15 d cultivation period using 2% salinity simulated eutrophication water. For the 4% salinity simulated water, the total phosphorus was not able to be removed and was even higher in the effluent; and the total inorganic nitrogen was only removed 17%. Thus, the algal-bacterial granules were efficient for removing nitrogen and phosphorus in 2% salinity eutrophication water but were not effective for 4% salinity water. High levels of filamentous algae proliferation growing on the surface of the granules was primarily responsible for the good performance in 2% salinity water. However, the lipid accumulation was greatly enhanced (reactor R2 at a 27.6% increase and reactor R4 at a 107% increase) for both granule types due to the algal growth. Thus, treatment of the salty eutrophication water can also greatly increase the added-value of the algal-bacterial granules.

Heat treatment of wood materials is generally performed to improve the physical, mechanical, chemical, surface, thermal, and crystallinity characteristics. In this way, the usage areas of wood material in different purposes can be expanded by means of heat treatment. The goal of this study was to determine the physical, mechanical, chemical, crystallinity, and surface properties of heat-treated Scots pine (Pinus sylvestris L.) wood. The test samples were heat-treated at 120 °C, 150 °C, 180 °C, and 210 °C for 4 and 6 h in a laboratory-scale oven. The shrinking and swelling chracteristics of wood was decreased as a function of heat treatment processes. Bending strength, compression strength, and modulus of elasticity decreased. In addition, lignin ratios and crystallinity index increased as temperature and duration of the treatment were increased. Consequently, heat-treated wood materials can be used in various areas by developing some of their properties.

The cellulolytic bacterial flora present in the rumen of Inner Mongolian sheep are thought to have a high degree of cellulose-degrading activity because of their foraging feeding regimen. However, there are no report on the genetic and species composition of the cellulolytic bacterial flora. In this study, cellulolytic bacteria were isolated from the rumen of Inner Mongolian sheep using a combined method of transparent zone and filter paper degradation. Twenty-two strains were identified via morphological, physiological, and biochemical tests. Ten strains were further identified via DNA (G + C) mol%, together with 16S rDNA gene sequencing analysis. Four types of extracellular and total cellulase activities of representative strains were determined. The results demonstrated that the isolates included Butyrivibrio fibrisolvens, Rumincoccus albus, R. flavefaciens, Fibrobacter succinogenes, and Clostridium polysaccharolyticum. A big proportion of cellulolytic Butyrivibrio fibrisolvens was found in the rumen of Inner Mongolian sheep. This was the first study to analyze the cellulolytic bacterial flora in the rumen of foraging Inner Mongolian sheep. These results indicated that the rumen of Inner Mongolian sheep represents an attractive source for cellulolytic microorganisms and enzymes, and the research results have a certain guiding importance for the efficient degradation of cellulosic materials.

Powder coating is environmentally friendly and safe in terms of human health and is used especially on home appliances and in the automotive sector. Because of these advantages, recent studies have expanded work on the application of powder coating on non-conductive surfaces. Within the scope of this research, low temperature curing (120 °C to 130 °C) was applied on wood-based composite panels of medium-density fiberboard (MDF), particleboard, and plywood to facilitate conductivity. Epoxy, polyester, and hybrid (epoxy-polyester) types of powder paint and water-based liquid paint (control group) were applied to the surface of materials. Panels coated with the powder coatings were compared to the panels coated with the water-soluble acrylic resin coating. The prepared samples were analyzed for performance properties. The best results for thickness swelling, water absorption, adhesive strength, abrasion, and scratch resistance were found for the plywood coated with water-based liquid paint, MDF coated with polyester-based powder paint, plywood coated with hybrid powder paint, particleboard coated with hybrid powder paint, and plywood coated with epoxy powder paint, respectively.