Ratio Of Rice Husk Research Articles

Fabrication of a flexible inner prosthetic socket via the FGM technique

Purpose The purpose of this study was to fabricate a flexible inner socket with enhanced stiffness and hardness distribution by using the functional gradient method (FGM). The FGM technique can improve the comfort and flexibility of amputees through the use of a socket that is built via the direct method. Design/methodology/approach Six flexible inner socket samples were fabricated with varying weight fractions of rice husk ash-to-silicone rubber. The tensile strength and hardness of each sample were assessed. Then, numerical analyses were conducted using SOLIDWORKS software to evaluate the pressure distribution on the inner and outer layers of the flexible socket. Findings The hardness and stiffness of the fabricated flexible inner socket gradually increased with the weight ratio of rice husk ash-to-silicone rubber, so when it was in contact with the skin, it approximated the stiffness and hardness of the skin to ensure comfort, and when reaching a higher value in the socket contact layer, it prevented penetration through the flexible inner socket. In addition, the pressure distribution at the external layer of the flexible inner socket has improved. Research limitations/implications A budget of US$500 limited the research to create a flexible inner socket that keeps the socket from penetrating the skin. Practical implications The FGM technique created a flexible inner socket that balances hardness and stiffness to ensure comfort and prevent wounds for its users, lower limb amputees. The commercial value resides in the accessibility of a secure and comfortable flexible inner socket for amputees worldwide, enabling them to overcome the issue of excessive stiffness typically associated with sockets made using the direct method. Originality/value This study introduces the use of FGM to fabricate a flexible inner prosthetic socket with enhanced stiffness and hardness distribution. The approach of using varying weight fractions of rice husk ash-to-silicone rubber to improve the comfort and flexibility of prosthetic sockets is a novel contribution to the field. Given the high stiffness of flexible internal sockets and their ability to maintain flexibility in the part in contact with the skin, such sockets manufactured using this method prevent pain and skin ulcers that previously occurred when sockets are manufactured via the direct method.

THE DETERMINATION OF THE OPTIMAL COMPOSITION OF AN ARBOLITE WALL PANEL USING MATHEMATICAL METHODS AND THE CALCULATION OF ITS STRESS STATE

In the article, the optimal composition of the arbolite mixture was determined using a preliminary mathematical method for the manufacture of wall panels. With the help of optimal compositions, wall panels were manufactured and its stress state under load was calculated. For the production of arbolite products, the advanced technology of pressed arbolite, manufactured by conveyor method, has been applied. Using the methods of mathematical planning of experiments, the optimal composition was determined – the ratio of rice husk and a multicomponent binder with high strength. A method for calculating the stress state of wall plates based on rice husk and its straw with an internal thermal insulation layer of class B1 arbolite has been developed. Formulas for determining the distribution of tangential stresses along the longitudinal axis of a wall panel along its thickness are obtained. Deviations of the wall plate under the action of an off-center longitudinal load are determined. An experimentally developed method for calculating wall plates has been tested and confirmed. Experimental data on the testing of wall panels based on rice husk and straw of natural size have shown sufficient reliability and adequacy. The water absorption of arbolite based on rice husk and multicomponent binder was 24%, and the thermal conductivity λ = 0.18-0.19 W/ (m·oC). The resulting arbolite has a frost resistance of 30-35 cycles.

Biomass nanoarchitectonics with activated rice husk char for nanoporous carbon as electrode material: Enhancing supercapacitor electrochemical performance

Nanoporous carbon from activated rice husk char was prepared via KOH activation at different ratios of rice husk: KOH, for using as electrode material in supercapacitor. The electrode could exhibit high performance in 6 M KOH aqueous electrolytes, particularly in terms of specific capacitance and power density. The Brunauer-Emmett-Teller (BET) analysis showed a high specific surface area of 2833 m²/g with a mesoporous structure in a sample activated with a 1:3 ratio of rice husk to KOH. In this sample, a high specific capacitance of 195.36 F/g was obtained at a current density of 1 A/g with excellent cycle stability of 99.87 % after continuous charge/discharge test for 10,000 cycles at 10 A/g. Furthermore, the fabricated symmetric coin cell exhibits a power density of 526.88 W/kg and an energy density of 14.77 Wh/kg. The practical application of this cell is demonstrated by its ability to power a 3 V LED light bulb for over 900 s.

Effect of Water and Rice Husk Ratio in Water-Based Planting Medium on Growth of Three Rice Varieties (Oryza sativa L.)

The agricultural sector faces two serious threats: declining production due to agricultural land conversion and water shortages due to global warming. Therefore, an agricultural system that accommodates the use of vacant land and water saving, in this case, urban farming with the use of soil-less media can be applied. In recent studies, both innovations have shown positive results in various commodities but have not been explored much specifically for rice crops. This study observed the effect of soilless media application (mixed water and rice husks media) on the growth of rice. This experiment was conducted in Sumber Jeruk, Jember (altitude 281 m asl, temperature 21-31°C, RH 65-75%), January-June 2022. The experiment used a completely randomized design with two factors and three replications. The first factor was the ratio of water to rice husk (1:0; 4:1; and 8:1). The second factor was rice varieties (Inpari 46, IR 64, and Mapan 05). The combination of Mapan 05 and media ratio 4:1 showed the highest result on shoot fresh weight (351.95 g) and root fresh weight (346.35 g). Meanwhile, the highest number of root length (45.20 cm) was found in the combination of Mapan 05 and media ratio 8:1. Moreover, Mapan 05 (93.94 cm) and Inpari 46 (93.88 cm) showed no significant difference in plant height. It can be concluded that soil-less media 8;1 promotes the highest result on rice plant growth observed.

Effect of Effective Microorganisms in Fermentation of Rice Husk and Anchovy Head Using Lab-scale Treatment

The rice husk and anchovy filet industry is one of the world’s most successful industries and generates many biowastes with valuable bioproducts. Combining effective microorganisms (EM) with anchovy head (AH) and rice husk (RH) will produce a beneficial fertilizer and make nutrients more valuable to the plant. Thus, this study aims to determine the most effective anchovy head and rice husk treatment ratio for agricultural applications to reduce waste disposal from anchovy heads and rice husks worldwide, which may cause environmental problems. In this study, rice husk and anchovy head were fermented at five different ratios of treatment weight for 25 days: Treatment A with 100% AH, treatment B with 100% RH, treatment C with 50% AH:50% RH, treatment D with 70% AH:30% RH, and treatment E with 30% AH:70% RH. The pH, temperature, and number of colonies of every treatment were measured every 0, 5, 10, 15, 20, and 25 days. This study shows that treatment D with a ratio of 70% AH: 30% RH is the most suitable based on pH range within 6–8.5, consistently increasing temperature and the highest number of colonies to be applied to plants. The ratio of rice husk and anchovy head of treatment D in this study can be used further by other researchers to discover their potential, especially for the agricultural industry.

Investigating the Influence of Distributor Type, Particle Size and Rice Husk Percentage on Fluidized Beds through Cold Fluidization Experiments

This work studies a fluidization system through cold experiments by using a mixture of rice husk and sand to investigate three parameters: type of bed distributor (perforated plate and plate with Tuyere-type injectors), sand granulometry (mean diameters of 324 µm and 647 µm) and rice husk mass ratio (from 1% to 10% of rice husk). The results reveal that the perforated distributor plate achieved a lower minimum fluidization velocity. However, the plate with Tuyere injectors generated better mixing, thus reducing possible stagnation points. An increase in the mean diameter of the sand raises the minimum fluidization velocity but also facilitates the formation of preferential channels. As for the rice husk mass ratio, values of over 5% cause stagnation points and preferential channels. It was also found that the relation between minimum fluidization velocity and rice husk ratio follows an exponential behavior, and an equation was developed to better describe their relation.

Development and Characterization ofAgro-AlliedRice Husks andGroundnut ShellWaste Briquettes

Briquetting of agro-residues can alleviate some of the problems of energy shortage being encountered world-wide. The briquettes are essentially manufactured to provide cheap energy to the various sectors. Most importantly, to the domestic households that are finding it difficult to purchase the other sources of energy because of their cost. In this research the briquettes wereproduced in a briquetting screw press –BSP, using a manually operated piston and cylindrical shape Mould. The individual materials weremixed thoroughly in a ratio of rice husk: groundnut shell (RH:GS) as follows: 100:00; 70:30; 50:50;30:70; and 00:100.A fixed quantity of each mixture wereseparately hand-fed into a manually operated closed-end piston press to compact the briquettes. Thereafter, the briquettes wereejected and placed on drying racks and left in the sun for drying. The moisture content, ash content, volatile matter, fixed carbon, ignition time,flame propagation time, calorificvalue and water boiling test were investigated to determine the physical and thermal properties of the briquettes produced. The results of the investigation showedthat moisture content of the briquettes ranged from 3.96 –5.65%, the calorific value ranges from 130, 63.56–141, 62.87kJ/kg, the range of ash content is 6.10 -9.32 %, for fixed carbon is 7.67 -20.20 %, the ignition time ranges from 238-270sec and the rangesfor water boiling test time is 10.57m, –13.37m. These values satisfactorily comparewell with values obtained by other researchers in the literature. Therefore, the rice husk -groundnut shell briquettes are good alternative source of thermal energy for cooking. It is an economical and also an environmental friendly source of energy and waste disposal.

Composite ash from coal and rice husk co-firing plants: A model source to produce Molecular Sieve 4A

Amongst the currently existing alternative renewable sources for energy production, biomass is a great focus of interest. Over the past few decades, the depletion of coal from natural reservoirs has created an alarming situation in India. Parallelly, the lack of concrete methodologies for the disposal of fly ash generated at these power plants is still a critical setback. To remediate, most majorly developing countries are adopting the route of combusting agro-waste with coal to generate energy. The post-combustion leftover at these power plants is referred to as composite ash expects to cause devastating impacts on the environment alike coal fly ash to a certain extent. On the contrary, Molecular Sieve 4A (MS 4A) or alumino-silicate resin emerged as a chart-topping product viz. that caters to a vital role in ion exchange, adsorbents, membranes, and catalysis due to its elite structural properties. Though, several attempts have been reported earlier to produce MS 4A using coal ash; the practical process is yet to be in commercial practice. The objective of the current paper is mainly focused on the eco-friendly pathway to synthesize MS 4A using composite ash samples pertaining to the variable ratio of rice husk to coal as feed and their corresponding effect on the physicochemical properties of zeolite samples. The investigation studied using XRD, SEM, IR, and Particle size analyzer evidently indicates a significant resemblance of composite ash sourced MS 4A samples with the commercial standard.

Biomass and low-density polyethylene waste composites gasification: Orthogonal array design of Taguchi technique for analysis and optimization

This modeling study explores and optimizes the performance of the gasification of a rice husk and low-density polyethylene waste composite utilizing an orthogonal array design of a Taguchi technique. This modeling study uses a signal to noise ratio analysis to optimize the gasification of rice husk and low-density polyethylene waste composite and utilizes an analysis of variance approach to identify the most important factors contributing to the process. It is shown that the composition ratio of rice husk and polyethylene waste contributes significantly to the gasification performance. Increasing composition ratio of rice husk and polyethylene waste improves hydrogen concentration, decreases carbon dioxide concentration and enhances carbon monoxide concentration. Energy efficiency is enhanced and normalized carbon dioxide emission is improved by increasing composition ratio of rice husk and polyethylene waste. The gasification of rice husk and low-density polyethylene waste composite is efficient (total energy efficiency of 77.6%) and clean (normalized carbon dioxide emission of 2.1 g/mol, based on the composite entering the system) at its multi-objective optimum conditions. The research results support the development of a system for gasification of biomass and plastic waste composites utilizing orthogonal array design of a Taguchi approach.

Study of co-pyrolysis kinetics, synergetic effects, and thermodynamics of coal and biomass blends

ABSTRACT The present work investigates the thermochemical conversion characteristics, reaction kinetics, and thermodynamic behavior of coal and biomass (Rice husk (RH)) blend pyrolysis in a TG reactor. Three different proportions of biomass (75, 50, and 25%) are blended with sub-bituminous Indian coal for the co-pyrolysis study. Pure coal and pure RH pyrolysis is characterized by three reaction stages, whereas the blended sample shows a four-stage thermal degradation reaction. A significant synergy is not found in the present study. Model-free techniques (FWO, KAS, and Starnik) are used to estimate the activation energy for various blending mixtures of the feed samples. The activation energy obtained for the equal mass ratio of coal and RH using the KAS, FWO, and Starnik methods is 61.45, 76.58, and 75.54 kJ/mol, respectively. The reaction order for coal: RH blend 25:75, 50:50, and 75:25 is estimated to be 4, 2.4, and 1.3, respectively. The favorable activation energy (Eα ) is found for the blending mixture of 50% coal and 50% RH. The positive value of ΔH indicates the endothermic nature of pyrolysis. The positive and negative values of ΔS indicate the complexity and nonspontaneous nature of coal and biomass blend pyrolysis. The average Entropy (ΔS) for an increasing % of coal is decreasing and the value comes to negative for 75% coal, indicating that thermal equilibrium is favorable for a higher % of coal.

Influence of biomass on coal slime combustion characteristics based on TG-FTIR, principal component analysis, and artificial neural network

The development and utilization of solid waste is an effective way to solve the severe environmental and energy crisis. In this study, Thermogravimetry - Fourier transform infrared spectrometry (TG-FTIR) was used to carry out the co-combustion experiment of coal slime and rice husk under different mixing ratios. With the increase of the mass percentage of rice husk in the sample, the initial ignition temperature and burnout of the sample decreased, and the comprehensive combustion performance improved gradually. The dominant reaction in the co-combustion of coal slime and rice husk was determined by statistical method. When the mass percentage of rice husk in the mixture is between 30 and 90 %, it can inhibit the release of NOx and SO2. Taking Kissinger-Akahira-Sunose method as an example, the calculated average activation energies of coal slime and rice husk combustion are 105.66 and 148.93 kJ/mol respectively. With the increase of the mixing ratio of rice husk in the blend, the combustion mechanism of the sample changed. Finally, the mean absolute error, root mean square error and determination coefficient of the artificial neural network model are 0.52697, 0.67866 and 0.99941 respectively.

Microwave co-pyrolysis of PET bottle waste and rice husk: effect of plastic waste loading on product formation

This research work is focused to understand the role of microwave susceptor-assisted pyrolysis on polyethylene terephthalate (PET) bottle waste with rice husk (RH) valorization. Microwave pyrolysis/co-pyrolysis experiments were conducted at 450 W microwave power using a graphite susceptor. Effects of PET: RH ratio and total mass of co-pyrolysis feed mixture were thoroughly investigated. Mass and energy yields of bio-crude, char, and gas were evaluated. Microwave energy consumption and energy efficiency of pyrolysis were also evaluated. Pyrolysis energy efficiency is higher at 40 g (73–76%) compared to 20 g (53–75%) of co-pyrolysis feed mixture. The heating value of bio-crude was high (34–36 MJ/kg) due to carbon (79–83 wt%) and hydrogen (5–6 wt%) rich compounds. Bio-crude composition significantly varied with PET: RH ratios. Co-pyrolysis promoted the formation of aromatic oxygenates and biphenyl hydrocarbons. The selectivity of biphenyl hydrocarbons (29.2%) is high at an equal PET: RH ratio. The selectivity of hydrocarbons obtained at the 20:20 (PET: RH) ratio is found to be 47.5%. The selectivity of aromatic hydrocarbons obtained in microwave pyrolysis (47.9%) of PET is higher compared to conventional pyrolysis (8%). In microwave pyrolysis of RH, the high selectivity of aromatic oxygenates (73%) was obtained. Whereas, in conventional pyrolysis, the formation of aliphatic oxygenates (36.5%) was observed. This research would provide an understanding of waste valorization using the co-pyrolysis platform.

A comparative approach in the utilisation of rice husk and empty palm bunch in the biomass boiler

Growing world’s population has immense contribution towards world economy and energy utilisation. The enormous usage of conventional fuel has contributed many environmental problems such as greenhouse gas emission (GHG), world climate change, and deterioration of human health. Recent study focuses on the generated power from EPB compared with methane in a typical biomass boiler. Also, there are very limited studies on the Air to Fuel (ATF) ratios value in boiler operation. In this paper, empty palm bunch (EPB) and rice husk (RH) have been selected as biomass fuel in the biomass boiler. The same recommended parameters of boiler and turbine was chosen for both EPB and RH feedstocks from previous study. Overall, the study proven to produce about 33% and 25% of energy from EPB and RH of what a methane (CH4) can produce from the same amount of feeding rate, respectively, with EPB producing 13.31% of higher turbine power than RH. This directly contributes to the technical feasibility and adaptability of environmentally friendly elements by seizing the opportunity of carbon emission of conventional fuel and replacing it with natural resources such as EPB and RH which are part of the biomass fuel replacement regime. However, ATF ratio of RH is significantly minimal of what a CH4 and EPB utilised to burn 1 kg of fuel. Therefore, EPB and RH would be suitable for future renewable biomass feedstock in comparison with conventional fuel for power generation purposes.

NOx emission from the combustion of mixed fuel pellets of Fenton/CaO-conditioned municipal sludge and rice husk

Sludge incineration technology is facing the problem of gaseous pollutant discharge. The control of NOx emissions is the key to reducing the impact of sludge combustion on environmental pollution. In this study, Fenton/CaO was used to condition municipal sludge, which was subsequently mixed with rice husk to fabricate briquette fuel for combustion experiments. The effects of the conditioner dosages, mass ratios of the rice hull to sludge, and the combustion temperatures on NOx emissions from briquette combustion were studied. The results showed that the NOx emissions decreased with increasing doses of conditioned sludge. In addition, with an increase in the rice husk ratio in the briquette, the NOx emissions decreased and the conversion rate increased. Additionally, with an increasing combustion temperature, the combustion of molded fuel became more complete. The NOx emission of conditioned sludge combustion was reduced by approximately 1.3 times compared with that of the sludge alone. Using the response surface methodology, the optimized conditions were obtained as follows: the rice husk mixing ratio is 43.8%, the Fenton/CaO conditioner dosage is 220 mg/g, and the temperature is 829 °C. The minimum NOx emission concentration was predicted to be 0.845 mg/g. The NOx emission laws observed from the combustion of mixed fuel pellets are believed to provide basic data for a new sludge treatment method.

Preparation of magnetic nanoparticle biocomposites using rice husk and sugarcane bagasse fibers as the matrix

Fiber is one of the important components to construct a matrix structure. Biomass is a potential material as a fiber resource for matrix. Rice husk and sugarcane bagasse consist of 36.6 % and 60% cellulose, respectively. This current research focused on evaluating the production of amine functionalized magnetic nanoparticle biocomposites produced by mixture of rice husk (RH) and sugarcane bagasse (SB) fibers. First, RH and SB fibers were dried and crushed close to 60 mesh for each, followed by a delignification at 80 °C for 2 h in 1% w/v of NaOH. Through by one-step solvothermal process, it was done by adding delignified ratio of RH and SB fibers (1:1; 1:2; 1:3; 1:4) to mixture of ethylene glycol, FeCl3.6H2O, and 1.6-hexanediamine at 200 °C for 6 h. The magnetic nanoparticles appeared on the fibers surface which contained 97.97% Fe. The magnetite was formed proved by the specific peaks at 36°, 43°, and 57° by X-Ray Diffraction.(XRD). The Fourier Transformed Infrared (FT-IR) identified N–H bending vibration and Fe-O in the biocomposites at 1640 cm−1 and 582 cm−1, respectively. The restructure of matrix, iron, and amine groups on the biocomposites surface can affect the adsorption capacity of various waste water treatments.

Preparation and evaluation of particleboard from insect rearing residue and rice husks using starch/citric acid mixture as a natural binder

This study evaluated the feasibility of manufacturing particleboard from the combinations of insect (black soldier fly larvae) rearing residue and rice husks at different ratios using citric acid/tapioca starch as a natural binder. Physical and mechanical properties of particleboards including density, moisture content, water absorption, thickness swelling, modulus of rupture, modulus of elasticity, internal bond strength, and screw withdrawal resistance were investigated. The results showed that the increase of insect rearing residue significantly increased the water absorption and thickness swelling and decrease the modulus of rupture. The modulus of elasticity, internal bond strength, and screw withdrawal resistance was slightly enhanced when the ratio of insect rearing residue was increased from 10 to 30 wt% with a corresponding reduced ratio of rice husk in the particleboards. Nevertheless, the modulus of elasticity, internal bond strength, and screw withdrawal resistance remarkably decreased when the ratio of insect rearing residue in the boards was over 30 wt%. Among all prepared particleboards, only particleboard B which was composed of 20 wt% insect rearing residue, 50 wt% rice husk, and 30 wt% binder met all the JIS A 5908 requirements for basic particleboard type 8. Based on the results, although further improvements are required, using insect rearing residue combined with agroindustrial wastes for particleboard manufacturing is feasible and possesses the patentability to mitigate the issues associated with deforestation and shortage of raw materials.

Journal Vol – 15 No -7, July 2020 Journal > Journal > Journal Vol – 15 No -7, July 2020 > Page 6 PERFORMANCE AND EMISSION CHARACTERISTICS OF GASOLINE-ETHANOL BLENDS ON PFI-SI ENGINE Authors: D.Vinay Kumar ,G.Samhita Priyadarsini,V.Jagadeesh Babu,Y.Sai Varun Teja, DOI NO: https://doi.org/10.26782/jmcms.2020.07.00051 admin July 26, 2020 Abstract: Alcohol based fuels can be produced from renewable energy sources and

Journal Vol – 15 No -7, July 2020 Journal > Journal > Journal Vol – 15 No -7, July 2020 > Page 6 PERFORMANCE AND EMISSION CHARACTERISTICS OF GASOLINE-ETHANOL BLENDS ON PFI-SI ENGINE Authors: D.Vinay Kumar ,G.Samhita Priyadarsini,V.Jagadeesh Babu,Y.Sai Varun Teja, DOI NO: https://doi.org/10.26782/jmcms.2020.07.00051 admin July 26, 2020 Abstract: Alcohol based fuels can be produced from renewable energy sources and

Microwave-assisted Acid-catalyzed Hydrolysis of Hemicelluloses in Rice Husk into Xylose

The development of an environmentally benign process for the hydrolysis of hemicelluloses into xylose could be one of the key technologies for making full use of biomass in the future. This paper studies dilute acid hydrolysis of hemicelluloses in rice husk (RH) into xylose using microwave radiation. Fourier transform infrared-attenuated total reflection spectroscopy was employed to quantitatively analyze xylose. The influences of hydrolysis parameters such as temperature, time, acid concentration, and ratio of RH to sulfuric acid on the yield of xylose in acid hydrolysis of RH were also investigated. The optimum hydrolysis conditions of hemicelluloses in RH to xylose are as follows: 4 wt% of H2SO4 concentration, 150 °C hydrolysis temperature, 25 min reaction time, and 1:7 ratio of RH (g) to H2SO4 (mL). Under optimum hydrolysis conditions, a yield of 32.96% xylose is obtained.

The influence of K2CO3 to rice husk ratio for CO2 adsorption in fixed bed column

Carbon dioxide emissions contributed by fossil fuel, have become a severe concern in relation to global warming and health issues. High content of CO2 will caused low content of heat value. This study is to reduce the concentration of CO2 gas by adsorption using K2CO3 rice husk. The method used is adsorption using a laboratory scale fixed bed column equipment at atmospheric condition and room temperature. The adsorption column was filled with K2CO3 and rice husk which composition (50: 8; 75: 8; 100: 8; 125: 8) grams, CO2 gas flowed from the bottom of the column which flow rate 9 liter per minutes (LPM). Then the sample was taken at the top of the column every 5 minutes. It showed that the highest adsorption capacity is 7.54 percent CO2 removal/gr adsorbent which amount of K2CO3 adsorbent 50 gr at 9 LPM CO2 inlet flow rate. It showed that most adsorbents have the most active sites to adsorb CO2. It also showed that K2CO3 50 gr have the longest breakthrough time than others amount of K2CO3.

Properties of Board Manufactured from Sawdust, Ricehusk and Charcoal

In this study, the environmentally friendly material charcoal was added to ricehusk, an agricultural by-product, and sawdust, which emerges during the sawing process, to produce board by mixing ratio and concentration levels of ricehusk and charcoal; it then investigated its physical properties for development purposes and achieved the following results. The water absorption and thickness swelling of the compounded board produced per adding ratio of ricehusk and charcoal showed a gradually decreasing tendency along with the increase in adding ratio of the charcoal, and as the density of the compounded board increased, the water absorption decreased, while the thickness swelling increased. The internal bond strength of the compounded board had indicated its highest value of 0.49N/mm2 at the density of 0.7g/cm3. This satisfied the quality standard for KSF 3104 Particleboard. The internal bond strength of the compounded board manufactured per adding ratio of ricehusk and charcoal showed a steady decrease with the decrease in the adding ratio of ricehusk, and an increase in the addingratio of the charcoal. Also, in cases when the ratio of the ricehusk and charcoal by KSF 3104 quality standard were 35:5 and 30:10, it satisfied the quality standard of 15.0-type, whereas it satisfied the 13.0-type quality standard if the ratios were 25:15 and 20:20. It showed a tendency of increasing hardness of the compounded board with the increase in density, and decreasing hardness with the increase in the adding ratio of the charcoal.