To investigate the effect of melamine resin impregnated paper waste on physical and mechanical properties of medium-density fiberboard (MDF), a mixture of melamine resin impregnated paper waste and wood fibers in the ratio of 0.100, 10/90, 20/80, 70.30 was used. After g More
To investigate the effect of melamine resin impregnated paper waste on physical and mechanical properties of medium-density fiberboard (MDF), a mixture of melamine resin impregnated paper waste and wood fibers in the ratio of 0.100, 10/90, 20/80, 70.30 was used. After gluing the fibers with urea-formaldehyde adhesive in 10% (relative to the dry weight of the fibers), the fiber cake in a laboratory press at a temperature of 170 °C, under the pressure of 35-40 bar and pressing time of 6 min to they were compressed to a thickness of 15 mm. The results obtained from zeasuring the physical and mechanical properties of the boards showed that increasing the amount of melamine resin impregnated paper waste in the boards led to increase the modulus of rupture, modulus of elasticity, internal bonding, while the thickness swelling after 2 and 24 hours of immersion was decreased. Therefore, the findings of the present study statistical analysis showed that the best treatment in this study is the use of 20% melamine resin impregnated paper waste in the production of medium-density fiberboard, while achieving the desired levels of physical and mechanical properties specified in the standard range related to this type of board, can be prevent waste loss and environmental pollution.
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Background & Objectives: Formaldehyde is a toxic and hazardous compound and s known as one of the mutagenic and carcinogenic agents in living creatures. Among a variety of procedures designed for the elimination of contamination, biological removal is capable of con More
Background & Objectives: Formaldehyde is a toxic and hazardous compound and s known as one of the mutagenic and carcinogenic agents in living creatures. Among a variety of procedures designed for the elimination of contamination, biological removal is capable of converting pollutants to innocuous and nontoxic substances using less amount of energy and chemicals. This study was aimed biodegradation of formaldehyde by the bacteria isolated from Wastewater of Paint Production (Pars Negin Nama). Materials & Methods: In this analytical study, samples were taken from paint production factory effluent. The samples were added to CM and MSM media to isolate bacteria. The bacteria were analyze based on morphological and biochemical characteristics. The bioregdaration ability of bacteria in MSM containing formaldehyde media was evaluated in absorbance at 600 nm using a spectrophotometer. The identity of bacteria was determined based on sequencing of 16SrRNA. Results: The result showed that the best formaldehyde degrading bacteria belonged to a new strain referred to as Bacillus sp. Safa. Toneka. This strain was able to degrade formaldehyde 1500 ppm formaldehyde in MSM agar and 2000 ppm formaldehyde in MSM broth after 48 hour. Conclusion: The results of the present research showed the ability of bacteria in the terms of the elimination of formaldehyde in contaminated areas.
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In this study, NiFe2O4-CdO compound nanoparticles were prepared through co-precipitation. The two variables of the synthesis method are, respectively, the temperature gradient reaching the temperature of the heat treatment of 500 ° C at 10°C/sec, 35°C/sec an More
In this study, NiFe2O4-CdO compound nanoparticles were prepared through co-precipitation. The two variables of the synthesis method are, respectively, the temperature gradient reaching the temperature of the heat treatment of 500 ° C at 10°C/sec, 35°C/sec and 60 °C/sec and the pure oxygen pressure as the heat treatment atmosphere for 0.5 hours, at 0.5 psi, 1 psi, and 1.5 psi. So, we found 9 samples, that the sample with the best sensitivity response to formaldehyde was characterized. X-ray diffraction, scanning electron microscopy, transition electron microscopy and X-ray fluorescence experiments were used to study the structure of these nanoparticles. X-ray diffraction experiment is confirmed formation of nickel ferrite and cadmium oxide phases. Scanning electron microscopy and transition electron microscopy experiments are confirmed nickel ferrite and cadmium oxide being nano-structure. NiFe2O4-CdO formula ratio is confirmed by X-ray fluorescence experiment. The sensitivity property of NiFe2O4-CdO nanoparticles for formaldehyde gas detection was studied at 50 °C. For testing the sensitivity of nanosensors, we used a laboratory 5 liters system with temperature and humidity control. This system equipped with a temperature control heater for heating sensors. Relationship between gas concentration (from 10 ppm to 200 ppm) and resistance change of nano sensor with the best response to formaldehyde was investigated, that this relationship was found linear.
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