Pine Wood Dust Research Articles

An experimental and analytical investigation to determine thermal conductivity of epoxy-filler composites for space applications

Thermal conductivity of epoxy-filler composite based Thermal Interface Materials (TIMs) is of utmost importance for thermal management systems used in space applications. Previous studies have shown that depending on the filler particle mixed into the epoxy, thermal conductivity of the composite can either be increased or decreased. Towards that, we have selected four different filler particles (micron sized) – aluminium, copper, zinc and silver to enhance the thermal conductivity of the base epoxy. Thermal conductivity of these 4 epoxy-filler composites has been determined experimentally using an indigenous developed setup at the temperatures ranging from 4.2 K to 323 K. The values have also been reported at various volume fractions (up to 15 %). In addition, after each preparation as the filler particles are mixed mechanically into the epoxy, they are randomly distributed, and this can affect the composite’s thermal conductivity (for the same volume fraction). The experimental determination of thermal conductivity for all the possible distributions is a time consuming, and cumbersome task. In the literature, thermal conductivity values are usually reported for few possible distributions. Therefore, we have developed a novel analytical model to predict all the possible values of thermal conductivity for a specific volume fraction. The predicted values compare well with our experimental data reported in this work at temperatures ranging between 338 K (above room temperature) to 4.2 K (liquid helium temperature). The predicted values are also in good agreement with the experimental values of different fillers such as red mud, pine wood dust and glass fiber etc. from the literature. Additionally, in comparison to other theoretical models like Lewis-Nielsen, Rule of mixture, and Poisson’s distribution, the present model predicts the thermal conductivity values more precisely. This work will be significant in the designing of components where heat transfer plays an important role towards the safety of the component.

Effects of spherical fillers reinforcement on the efficacy of thermal conductivity in epoxy and polyester matrices: Experimental validation and prediction using finite element method

AbstractThe creation of a theoretical heat conduction model for polymers embedded with spherical inclusions is described in this study. It also contains the experimental confirmation of the suggested correlation for utilizing the model to estimate the effective thermal conductivity (K) of such composites. According to ASTM‐E‐1530, composites are made with varying amounts of aluminium oxide and pine wood dust reinforced in polyester resin. The effective thermal conductivities (Keff) of the composites are then determined using the Unitherm TM model 2022. Ansys 19.R2 software is used to evaluate the effective thermal conductivity of these composites with a uniform filler distribution, while Digimat‐FE software is used determine the thermal conductivity values of such particle filled polymer composites with a random filler distribution. After comparison and validation with experimental data, these values are shown to be fairly good agreement with the theoretical values from the suggested correlation. The investigation is further expanded to determine the thermal conductivities for epoxy composites using wood apple shell dust and coir dust particle. Also epoxy and polyester composites reinforced with SiO2 and TiO2 have been investigated in the similar manner. The main thrust of this report to validate the numerical results of composites by varying numerous polymers. The thermal conductivity all the composites grow monotonically with increase in filler content. The thermal conductivity of silicon dioxide, titanium oxide, and aluminium oxide filled epoxy composites is measured as 1.5, 7, and 35 W/m‐K respectively.Highlights In this study spherical fillers are successfully used as a potential filler material in polyester composites The thermal conductivity predicted by proposed mathematical model of polyester is validated with measured value and found better agreement. The Ansys 19.R2 and digimat software are used to predict the thermal conductivity values of these composites. The mathematical model is further used to predict thermal conductivity of epoxy composites to check the accuracy of the model.

Experimental Study on Flame Spread of Pine Wood Dust Layer Under Horizontal Rotation Condition

ABSTRACT The rotating discs of wood polishing machines and the rotating bases of winding machines rotate horizontally during operation, and a layer of wood dust may be deposited on their surfaces. The study of flame spreading of wood dust layer in the rotating state has not been reported in the literature. Based on this situation, in this study, the flame spreading of pine wood dust layers in three particle size ranges under stationary and different rotating conditions were carried out and analyzed comparatively. The results show that the flame spreading speed of the pine wood dust layer from 74~100 micrometers positively correlates with the rotational angular velocity. The flame-spreading speed of a pine wood dust layer larger than 100 micrometers negatively correlated with the rotational angular velocity. This indicates that the flame spreading speed of the pine wood dust layer is affected by the combined effect of dust particle size and dust layer motion state. The flame propagation speed of the 74~100 micron pine dust layer was 3.3 mm/s when the rotational angular velocity was 0.167 rad/s, which was the maximum flame propagation speed in all experimental conditions. The maximum flame height of the pine dust layer in the rotating state was at least 55.6% higher than that in the stationary state.From the combined view of the three parameters of flame spreading speed, flame duration, and maximum flame height, the fire danger is greater in the rotating state than in the stationary state. Within a certain range, the larger the rotational angular velocity, the greater the fire hazard.

Evaluation of the adsorption capacity of surfactant-modified biomass in an aqueous acid blue 193 system

The study explored the capacity of modified pinewood dust (S-dust) for adsorbing acid blue 193 dye. The novel adsorbent was prepared via the insitu intercalation of quaternized ammonium copolymer (cationic surfactant) onto pinewood dust. The synthesized biosorbent was characterized using the Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersion X-ray (EDX) and Brunauer–Emmett–Teller (BET) surface area equipment. To establish the variable effects on the dye uptake, the ranges of solution pH, initial adsorbate concentration, contact time and adsorbent dosage were varied. The maximum monolayer adsorption capacity of 117.58 mg/g was recorded at pH 4.0, 0.1 g/L adsorbent dose and 2 h sorption duration. The process kinetics and isotherm modelling fitted best to the pseudo-first-order and Freundlich models, respectively. From the mechanistic/diffusion studies, intraparticle and pore diffusion mechanisms were respectively postulated at low and high initial adsorbate concentrations. Also, the occurrence of a nonspontaneous endothermic uptake process was inferred from the thermodynamics evaluations. Therefore, the effective acid blue 193 dye uptake onto novel S-dust was confirmed in this study.

Flammability and explosion characteristics of softwood dust

In technical terms, wood is a natural composite material with a polymer matrix, reinforced with fibres made of uniaxially oriented longitudinal cells. Due to the ease of obtaining and relatively low technological requirements related to its processing, wood is a common material used for various types of construction materials. An experimental investigation was carried out to determine the evolution of the ignition sensitivity and the explosion of three types of softwood dusts. Two of those dusts come from conifers and one from a deciduous tree. Complete fire characteristic requires several parameters describing wood dust behaviour under fire conditions including heat release rate (HRR), ignition time, or fire growth index. To determine those parameters, a cone calorimeter was used. Explosion characteristic was tested for representative wood as a dust sample in 20-L spherical vessel. Minimum ignition energy (MIE) was tested on MINOR II apparatus, which is a modified Hartman’s tube. Minimum ignition temperatures were tested with the use of layer ignition temperature apparatus and Godbert–Greenwald apparatus for minimum ignition temperature of a dust layer and dust cloud (MIT), respectively. Dust with the highest KST value, lowest MIE in the widest concentration range, and lowest MIT was pine wood dust. It also shows the shortest ignition time and a timespan between ignition and HRR peak.

Polysaccharide Composite Films Utilising Wood Waste.

This study aimed to investigate the effect of raw waste pine wood dust (Pinus sylvestris) from furniture production on polysaccharide biopolymer film properties. The obtained biocomposite films produced via the casting method were prepared with 20% glycerol and 0%, 5%, 10%, 15%, 20%, and 25% of added wood dust in relation to the dry starch matter. Wood dust composition and particle size distribution analysis were performed. In order to evaluate the material surface properties, tests were carried out using an atomic force microscope (AFM) and a contact angle goniometer. Utilising uniaxial tensile test methodology, the values for both tensile strength and Young's modulus were determined. In addition, the barrier properties, water solubility index, and colour were also investigated. The research showed that wood dust affected the functional parameters of the obtained biocomposites. A wood dust content increase causes the Young's modulus value to rise with a progressive decrease in the max. strain. The filler did not change the films' wetting properties, and each had a hydrophilic surface regardless of the additive amount. The bio-sourced composites obtained were non-toxic and environmentally neutral materials, suitable to be applied in the packaging industry as well as the agriculture sector.

Characteristics of Pinewood Dust Combined with Vinyl Ester Composites Through Material Testing and Machining

Natural fibre-reinforced polymer (NFRP) composites can be environmentally friendly and cost-effective alter-natives to synthetic fibre-reinforced composites. Major industries have expressed significant interest in the advancement of new natural fibre-reinforced composite materials. However, these materials perform poorly on their own and require further analysis since accessible information is lacking in the literature. This paper presents the results of previously reported works on natural fibre reinforced polymer composites, with strong attention to the types of fibres employed, the polymers used in the matrix, the treatment of fibres as well as the test parameters. The best proportion of composites is consequently selected. Composite materials are tested using a CNC router machine. Pinewood dust is combined with vinyl ester resin. A hand layup tech-nique is used to prepare the samples. The availability of relevant pinewood dust and the volume of pine wood dust to be used are first determined to continue with the experiment. According to the findings, the impact of machining performance is successfully evaluated by employing the tensile strength test, Charpy impact test, flexural strength test and surface roughness measurement. The findings are derived from the microscopic assessment of the surface roughness of pinewood dust (PWD) fibre reinforced vinyl ester resin.

Development and validation of a mathematical heat conduction model across polymer composites with spherical inclusions

This paper reports on the development of a mathematical heat conduction model for polymers embedded with spherical inclusions. It also includes the experimental validation of the proposed correlation for predicting the thermal conductivity(Keff)of such composite materials. Composites are prepared with different proportions of pine wood dust and aluminum oxide separately reinforced in polyester resin and their effective thermal conductivities are measured using UnithermTM model 2022 as per ASTM E-1530. The measured thermal conductivity of compositesare compared and are found to be in reasonably good agreement with the predicted values estimatedby the proposed mathematical correlation. Further, the study is extended to estimate the Keffvalues for a number of polymer composites with epoxy/polyester as matrices and coir dust/wood-apple shell dust as particulate fillers. Similarly, composites with TiO2 and SiO2 reinforcements have also been considered. This study reveals that the incorporation of micro-sized fillers greatly influences the heat transfer behaviour and thereby the heat conductivity of filled polymer varies with the inclusion of fillers. It also shows that the correlation developed and proposed in this paper performs well both for thermally conducting and insulating fillers.

Pilot-scale study on the influence of wood dust type on pressure drop during filtration in a pulse-jet baghouse

Abstract Experimental filtration processes were carried out to investigate the air flow resistance during separation of three types of wood dusts in a pilot-scale pulse-jet filter. Three types of dust were compared: dust from sanding pine wood, dust from sanding beech wood and dust from working particl,eboard. These dusts are characterized by different particle-size distribution. The resistance coefficient K1 was determined for the filter fabric used in tests. Basing on the results of pressure drop across the filter measured during the experimental processes in condition of three levels of filtration velocity Vf (0.0405; 0.0484 and 0.0583 m s−1) the specific dust cake resistance coefficient K2 was calculated. It value depends on the dust type and filtration velocity used. The lowest K2 (20,085 s−1) has pine wood dust at filtration velocity 0.0484 m s−1. While the highest value (28,925 s−1) was calculated at Vf = 0.0583 m s−1 for dust from working of particleboards.

Contamination of pine and birch wood dust with microscopic fungi and determination of its sterol contents.

Wood compounds, especially sterols, are connected with the level of contamination with microscopic fungi. Within this study, tests were conducted on wood dust samples collected at various work stations in a pine and birch timber conversion plant. Their contamination with mycobiota was measured as the concentration of ergosterol (ERG) by ultra performance liquid chromatography (UPLC). Another aim of this study was to assess the effect of contamination with microscopic fungi on the sterol contents in wood dusts. Analyses were conducted on five sterols: desmosterol, cholesterol, lanosterol, stigmasterol, and β-sitosterol using UPLC and their presence was confirmed using gas chromatography/mass spectrometry (GC/MS). The results of chemical analyses showed the greatest contamination with mycobiota in birch wood dust. We also observed varied contents of individual sterols depending on the wood dust type. Their highest concentration was detected in birch dust. The discriminant analysis covering all tested compounds as predictors showed complete separation of all tested wood dust types. The greatest discriminatory power was found for stigmasterol, desmosterol, and ergosterol.

Determination of thermal conductivity of pine wood dust filled epoxy composites

In the present investigation the Thermal conductivity in particulate filler filled (Pine wood dust) epoxy composites at different volume fractions (6.5%, 11.3%,26.8% and 35.9%) have been determined experimentally by using Forced Convection apparatus. The composites of pine wood dust particles of 150 micron size have been prepared by using hand-lay-up technique. The experimental results show that the incorporation of pine wood dust results in reduction of thermal conductivity of epoxy resin and there by improves its thermal insulation capability. From the experiments it is also observed that the composite with 35.9% volume fraction of pine wood dust exhibited lowest thermal conductivity i.e 0.246 W/m-0K on comparison to 6.5%,11.3% and26.8% volume fractions. Therefore the composite with 35.9% wood dust may be more suitable for insulation application. Experimental results (22mm pipe diameter) are also compared with theoretical models such as Rule of mixture model, Maxwell model, Russell model and Baschirow & Selenew model to describe the variation of thermal conductivity versus the volume fraction of the filler. All these models exhibited results close to each other at low dust filler content. On comparison, It has been found that the errors associated with experimental (26mm Dia.) along with all the above four models with respect to experimental ones (22mm Dia.) lie in the range of 19.60 to 44.10%, 0.76 to 12.10%, 1.86 to 5.12% and 8.24 to 19.68% respectively.

Sorption of four hydrophobic organic contaminants by biochars derived from maize straw, wood dust and swine manure at different pyrolytic temperatures

Sorption behavior of acetochlor (ACE), dibutyl phthalate (DBP), 17α-Ethynyl estradiol (EE2) and phenanthrene (PHE) with biochars produced from three feedstocks (maize straw (MABs), pine wood dust (WDBs) and swine manure (SWBs)) at seven heat treatment temperatures (HTTs) was evaluated. The bulk polarity of these biochars declined with increasing HTT while the aromaticity and CO2-surface area (CO2-SA) rose. The surface OC contents of biochars were generally higher than bulk OC contents. The organic carbon (OC)-normalized CO2-SA (CO2-SA/OC) of biochars significantly correlated with the sorption coefficients (n and logKoc), suggesting that pore filling could dominate the sorption of tested sorbates. SWBs had higher logKoc values compared to MABs and WDBs, due to their higher ash contents. Additionally, the logKoc values for MABs was relatively greater than that for WDBs at low HTTs (≤400 °C), probably resulting from the higher CO2-SA/OC, ash contents and aromaticity of MABs. Surface polarity and the aliphatic C may dominate the sorption of WDBs obtained at relatively low HTTs (≤400 °C), while aromatic C affects the sorption of biochars at high HTTs. Results of this work aid to deepen our understanding of the sorption mechanisms, which is pivotal to wise utilization of biochars as sorbents for hazardous organic compounds.

Mathematical model for evaluating effective thermal conductivity of polymer composites with hybrid fillers

A mathematical correlation for evaluating the effective thermal conductivity (keff) of hybrid polymer composites filled with two dissimilar particulate fillers is developed using the law of minimal thermal resistance and equal law of specific equivalent thermal conductivity. The estimations are validated with experimental results. Epoxy and polypropylene are chosen as matrix materials. Two conductive fillers, aluminium nitride (AlN) and aluminium oxide (Al2O3) and two insulative fillers, pine wood dust (PWD) and rice husk (RH) are chosen as filler in present study. Sets of thermoset polymer composites (epoxy based) and thermoplastic composites (polypropylene based) are fabricated by hand lay-up technique and compression molding technique respectively. keff of all the fabricated composites are measured by Unitherm™ Model 2022 tester as per ASTM E-1530. The measured values are than compared with the values obtained from the proposed mathematical model for 0–15 vol% filler concentration. While there is no theoretical model available in the literature so far for estimation of keff for polymer composites with hybrid fillers, it is encouraging to notice that the measured values are in close approximation with the values predicted by the model proposed in this work.

Measurement on Thermal Conductivity of Pine Wood Dust Filled Epoxy Composites

In the present investigation the thermal conductivity of composites of epoxy reinforced with pine wood dust (PWD) at different volume fractions are determined experimentally by using Lee’s apparatus. The composites have been prepared by using hand-lay-up technique. The principle of heat transfer by conduction through a bad conductor is equal to the quantity of heat transfer by radiation from the metallic disc has been applied. The experimental results show that the incorporation of pine wood dust results in reduction of thermal conductivity of epoxy resin and there by improves its thermal insulation capability. Experimental results are compared with Rule of mixture model, Maxwell model, Russell model and Wood side & Baschirow & Selenew to describe the variation of thermal conductivity versus the volume fraction of the fibre. All these models exhibited results close to each other at low dust content. It has been found that the errors associated with these models with respect to experimental ones lie in the range of 0.6 to 28.6%, 53.2 to 58.7%, 55.45 to 63.47% and 34.21 to 47.06% respectively. With addition of 6.5 Vol. %, 11.3 Vol. %, 26.8 Vol. % and 35.9 Vol.% of pine wood dust the thermal conductivity of neat epoxy resin was reduced by about 39.4%, 43.8%, 54% and 58.1% respectively.

Occupational asthma caused by IgE-mediated sensitization to multiple woods

Wood is a natural material that is able to trigger rhinitis and asthma in exposed subjects in occupational settings. This has been described with both soft and hard woods.1,2 Involvement of both low- and high-molecular-weight allergens has been reported, and the relevance of these is related with the wood type.1 There are cases where protein may be the responsible allergen. Crossreactivity between obeche and ramin woods3 and between obeche and latex4 has been shown. However, to the best of our knowledge, this is the first report of a multiple IgE-mediated sensitization to different woods that caused occupational respiratory symptoms in the same worker.

Evaluation and prediction of wear response of pine wood dust filled epoxy composites using neural computation

Inspired by the biological nervous system, an artificial neural network (ANN) approach is a fascinating computational tool, which can be used to simulate a wide variety of complex engineering problems such as tribo-performance of polymer composites. This paper, in this context, reports the implementation of ANN in analyzing the wear performance of a new class of epoxy based composites filled with pine wood dust. Composites of three different compositions (with 0, 5 and 10 wt.% of pine wood dust reinforced in epoxy resin) are prepared. Dry sliding wear trials are conducted following a well planned experimental schedule based on design of experiments (DOE). Significant control factors predominantly influencing the wear rate are identified. An ANN approach taking into account training and test procedure is implemented to predict the dependence of wear behavior on various control factors. This work shows that pine wood dust possesses good filler characteristics as it improves the sliding wear resistance of the polymeric resin and that factors like filler content, sliding velocity and normal load, in this sequence, are the significant factors affecting the specific wear rate. It is further seen that the use of a neural network model to simulate experiments with parametric design strategy is quite effective for prediction of wear response of materials within and beyond the experimental domain.

A computational and experimental investigation on thermal conductivity of particle reinforced epoxy composites

Abstract The finite element method (FEM) is a powerful computational technique for approximate solutions to a variety of “real-world” engineering problems having complex domains subjected to general boundary conditions. In this paper FEM is implemented to determine the effective thermal conductivity of particulate filled polymer composites and is validated by experimentation. A commercially available finite-element package ANSYS is used to for this numerical analysis. Three-dimensional spheres-in-cube lattice array models are constructed to simulate the microstructure of composite materials for various filler concentrations ranging from about 6 to 36 vol.%. Composites with similar filler contents are fabricated by hand layup technique by reinforcing micro-sized pine wood dust in epoxy resin. Guarded heat flow meter test method is used to measure the thermal conductivity of these composites using the instrument Unitherm™ Model 2022 as per ASTM-E1530. This study shows that the incorporation of pine wood dust results in reduction of conductivity of epoxy resin and thereby improves its thermal insulation capability. With addition of 6.5 vol.% of filler, the thermal conductivity of epoxy is found to decrease by about 19.8% and with about 36 vol.% of filler addition, a 57.3% reduction in thermal conductivity of neat epoxy is achieved. The experimentally measured conductivity values are compared with the numerically calculated ones and also with the existing theoretical and empirical models. The values obtained using finite-element analysis (FEA) are found to be in reasonable agreement with the experimental values.

Accumulation of eosinophils and T-lymphocytes in the lungs after exposure to pinewood dust

Exposure to wood dust within the woodworking industry has been shown to cause a variety of respiratory disorders. The aim of this study was to investigate the cellular effects in bronchoalveolar lavage (BAL) fluid and peripheral blood from healthy individuals exposed to pinewood dust. Eleven healthy volunteers were exposed to pinewood dust for 1 h in a whole-body exposure chamber. BAL fluid and blood cells were differentially counted and the expression of activation, adhesion and subset markers on alveolar macrophages and T-lymphocytes was determined 2-6 weeks before and 20 h after the exposure. Following pinewood dust exposure, the total BAL fluid cell concentration increased from 81.4 (64.1-97.5) x 10(6) cells x L(-1) (median (interquartile range)) to 195.3 (154.6-341.2) x 10(6) cells x L(-1). The BAL fluid T-lymphocyte concentration increased from 3.8% (3.5-6.5%) to 7.6% (4.9-11.2%), and BAL fluid eosinophil concentration from 0.0% (0.0-0.2%) to 1.8% (0.6-3.5%). Inhalation of pinewood dust leads to the recruitment of inflammatory cells to the airways of healthy individuals. The increase in numbers of eosinophils, T-lymphocytes and mast cells, i.e. cells of crucial importance to airway inflammation, in the lungs may be related to the increased risk of developing respiratory disorders among woodworkers.

Only few workers exposed to wood dust are detected with specific IgE against pine wood.

Our aim was to investigate the frequency of pine allergy in woodworkers with respiratory symptoms and to identify high molecular weight allergens in pine wood extracts. In a cross-sectional study we examined work-related respiratory symptoms in 2033 furniture workers and 474 controls by questionnaires. Clinical examination was performed in 365 wood dust exposed and 116 nonexposed subjects. Blood samples were collected for measuring pine-specific immunoglobulin (Ig)E by an immunoassay and Western blots. Eleven exposed and three nonexposed subjects had pine-specific IgE. In the group with clinically defined asthma eight persons (5.4%) had pine-specific IgE compared with six persons (1.8%) in the group without asthma (P < 0.05). In the groups with and without respiratory symptoms, 13 (3.8%) and one (0.7%) subject, respectively, had pine-specific IgE (P = 0.06). Western blots demonstrated pine-specific IgE to components in the molecular range of 14 - 100 kD in eight samples (all wood dust exposed). Five samples had pine-specific IgE against components in a 43 - 59 kD zone and against two bands at 27 and 29 kD that are candidates for major allergens. Some workers in the Danish furniture industry are specific IgE sensitized against pine wood dust. Pine-specific IgE probably explains a minor part of the respiratory symptoms in workers exposed to pine wood dust.