• Journal of Korean Society of Forest Science
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• v.56 no.1
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• pp.1-25
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• 1982

Plywood used for construction as a decorative inner material is inflammable and can cause fire accidents. causing destruction of human life and property. To diminish the fire disaster, fire retardant plywood is indeed required. In the methods of manufacturing the fire retardant plywood, a soaking method is occasionally used. However after soaking plywood into fire retardant chemical solutions redrying of soaked plywood is of the utmost importance. In this study 3.5mm and 5.0mm thickness plywoods were selected for fire retardant treatment. Treating solutions were prepared for 20% dilute solutions of ammonium sulfate, monoammonium phosphate, diammonium phosphate, borax-boric acid minalith, and water solution, 1-, 3-, 6-, and 9 hour-soaking treatments in borax-boric acid and minalith, and 6- and 9 hours in the other chemicals were applied and after the treatment hot drying was applied to treated plywoods at $90^{\circ}C$, $120^{\circ}C$ and $150^{\circ}C$ of press temperature. Drying rates, drying curves, water absorption rates of fire retardant chemicals, weight per volume and fire retardant degree of plywood were investigated. The results may be summarized as follows: 1) In the 9 hours-soaking treatment of fire retardants by hot and cold bath method, the chemical retentions of 3.5mm thickness plywood could be attained within the range ($1.125-2.25kg/(30cm)^3$) of minimum retention specification as follows: $1.353kg/(30cm)^3$ in monoammonium phosphate, $1.331kg/(30cm)^3$ in diammonium phosphate, $1.263kg/(30cm)^3$ in ammonium sulfate, $1.226kg/(30cm)^3$ in borax-boric acid. But the chemical retention, $0.906kg/(30cm)^3$, in minalith could not be attained within the range of minimum retention specification. And also in case of 5.0mm thickness plywood, chemical retentions, as $1.356kg/(30cm)^3$ and $1.166kg/(30cm)^3$ respectively, of ammonium sulfate and diammonium phosphate could be attained within the range minimum retention specification, but the other fire retardant chemicals could not. 2) In the 6- and - hours-soaking treatments of 3.5mm and 5.0mm thickness plywood, the drying curve sloped of chemical treated plywood was smaller than that of water treated. The drying rate related to thickness of treated plywood, was about three times as fast in 3.5mm thickness plywood compared with 5.0mm thickness plywood. 3) In the treatment at $120^{\circ}C$ of hot platen temperature, the drying rates of chemical-treated plywood showed the highest quantity in diammonium phosphate of 3.5mm and 5.0mm thickness plywood. But the drying rate of water treated plywood was highest during the 6- and 9 hours-soaking treatments. 4) The drying rate remarkably increased with proportion to increase of the platen temperature, and the values were respectively 1.23%/min., 6.54%/min., 25.75%/min. in hot platen temperature of $90^{\circ}C$, $120^{\circ}C$, $150^{\circ}C$ in 3.5mm thickness plywood and 0.55%.min., 2.49%/min., 8.19%/min. in hot platen temperature of $90^{\circ}C$, $120^{\circ}C$, $150^{\circ}C$ in 5.0mm thickness plywood. 5) In the fire retardant degree of chemical treated plywood, the loss in weight was the smallest in diammonium phosphate, next was in monoammonium phosphate and ammonium sulfate, and the greatest was in borax-boric acid and minalith. And the fire-retardant effect in burning time, flame-exhausted time and carbonized area were greatest in diammouniun phosphate, next were in monoammonium phosphate and ammonium sulfate, and the weakest were in borax-boric acid and minalith.

• Fire Science and Engineering
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• v.19 no.2 s.58
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• pp.105-110
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• 2005

We tested the char characteristics of fire retardant treated Douglas fir at each of five constant external irradiance levels $(10,\;15,\;20,\;25\;및\;35kW/m^2)$. A Cone heater was used to expose the wood specimens to the heat flux. The size of specimens is 100- by 100- by 50-mm and the kinds of specimens are non-treated wood(N) and treated wood(F2 and f4) by water soluble fire retardants. The water-soluble fire retardants were made from mixture of aqueous solutions of monoammonium phosphate, sodium borate and zinc borate, and those are used for immersion of Douglas fir. In result of test, char fraction of fire retardant treated Douglas fir showed a considerably low char fraction than it of non-treated wood irrespective of increase of external heat flux. And char fractions has low levels with increase of fire retardant content. Burning rate of non-treated wood(N) was showed a relatively high burning rate than it of fire retardant treated wood(F2 and F4). And difference of burning rate shown more rapidly in high external irradiance than low external irradiance. When the external heat flux is $35kW/m^2$, average char rate of non-treated wood is rapidly about twice than fire retardant treated wood. Water-soluble fire retardants mixed in this study find out it has fire suppression and adiabatic effect by char layer from results of char fraction, burning rate, and char depth and rate.

• Journal of the Korea Institute of Building Construction
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• v.17 no.1
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• pp.23-30
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• 2017

The aim of the research is to suggest an economical and sustainable method of reducing pH of recycled aggregate as an embanking and a covering materials. Because of the unhydrated cement based materials on the surface of the recycled aggregate, it causes a severe problem on environment with leaked high alkali water from embankment and covering by using recycled aggregate. In this research, to reduce the pH of recycled aggregate, regarding the recycled fine aggregate, eight different methods were tested and analyzed with three different categorized: natural treatment, artificial treatment, and chemical treatment. From the results of experiment, it was considered that the most efficient method of reducing pH of recycled aggregate was the chemical treatment using acid such as $CO_2$ acceleration or monoammonium phosphate (MAP), and diammonium phosphate (DAP). Especially, using MAP and DAP, fertilizers, is the most efficient method of reducing pH with its time duration and performance.

• The Journal of the Korea Contents Association
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• v.8 no.8
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• pp.285-292
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• 2008

This study was initiated to evaluate the Phosphorus(P) leaching potential in the putting green soils and P uptake by the turfgrass in the golf course using the P fertilizers. The turfgrass, Floradwarf bermudagrass(Cynodon dactylon L. PERS,) was planted and grown in the mixture of sand and peat moss in this lysimeter study. Five representative P fertilizers, such as, ammonium polyphosphate (APP), monopotassium phosphate (MKP), MAP(monoammonium phosphate), 0-20-20(liquid), and concentrated superphosphate(CSP, solid) were used in this study. Based on the total P quantity of leachate collected during the whole 12 weeks, MKP and APP are the first group of P fertilizers contributing to the leaching of P, then MAP and 0-20-20 are the second group of P fertilizers causing the P leaching. Finally, CSP is the third group of P fertilizer resulting in the P leaching. However, most of P applied and collected in the lysimeter were leached during the first period of two and four weeks, compared to that of P leached during the second period of six, eight, ten, and twelve weeks. Applications of MAP, APP and CSP, MKP and 0-20-20 in order produced the largest amount of total dry matter. However, APP, MKP and MAP, CSP and 0-20-20 in order showed the largest amount of P uptake. Therefore, based on the data of P leaching, dry matter production, and plant P uptake, it appears that CSP, 0-20-20, and MAP are the environmentally sound fertilizers recommended in the turfgrass putting green soil of golf course.

• Journal of the Korean Wood Science and Technology
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• v.13 no.4
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• pp.3-57
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• 1985

This research was conducted to examine the feasibility of developing fire retardant particleboard and complyboard. Particleboard were manufactured using meranti particle(Shorea spp.)made with Pallmann chipper, and complyboard meranti particle and apitong veneer (Dipterocarpus spp.). Particles were passed through 4mm (6 mesh) and retained on 1mm (25 mesh). Urea formaldehyde resin was added 10 percent on ovendry weight of particle. Face veneer for complyboard was 0.9, 1.6 and 2.3mm in thickness and spread with 36 g/(30.48 cm)$^2$ glue on one side. Veneers were soaked with 10 percent solution of five fire retardant chemicals (diammonium phosphate, ammonium sulfate, monoammonium phosphate, Pyresote and Minalith), and particles with 5, 10, 15 and 20 percent solution of five chemicals. Particleboard and complyboard were evaluated on physical and mechanical properties, and fire retardancy. The results obtained were summarized as follows. 1. Among five fire retardant chemicals treated to particleboard and complyboard, the retention of ammonium sulfate in 5 percent solution showed the lowest as 1.39 kg/(30.48 cm)$^3$ exceeding the minimum retention of 1.125 kg/(30.48 cm)$^3$ recommended by Forest Products Laboratory and Koch. 2. Particleboard and complyboard treated with diammonium phosphate showed higher modulus of rupture (MOR), modulus of elasticity (MOE), internal bond strength and screw holding power than those with the other chemicals. 3. MOR and MOE of complyboard treated with fire retardant chemicals were greater than those of fire retardant particleboard. 4. Thickness swelling of fire retardant complyboard was lower than that of fire retardant particleboard. 5. The moisture content of the boards treated with Pyresote and Minalith increased and with monoammonium phosphate reduced. 6. Fire retardant particleboard showed no ignition, and fire retardant complyboard started ignition, but time required to ignite was prolonged comparing the controlboard. Complyboard with only shell veneer treated showed ignition and lingering flame, but lingering flame time was shorter than controlboard. Complyboard with treated both core and veneer showed ignition but not lingering flame. 7. Flame length, carbonized area and weight loss were smaller than controlboard but had no significant difference among chemicals treated. 8. Temperature of unexposed surface of fire retardant particleboard was lowered with the increasing concentration of five chemicals. 9. Temperature of unexposed surface of fire retardant particleboard was lowered with the highest in Pyresote and the lowest in Minalith. 10. Temperature of unexposed surface of fire retardant complyboard was lower than that of controlboard.

• Korean Journal of Weed Science
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• v.32 no.1
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• pp.17-24
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• 2012

The study was conducted to investigate the effect of weed interference and starter fertilizer on subsequent soybean seed quality at the Agricultural Research Farm and Laboratory of Razi University, Kermanshah, Iran. Two factorial experiment was laid-outon a randomized complete block design with four replications. First factor was starter fertilizer levels (0 and 25 kg $ha^{-1}$) applied in the forms of monoammonium phosphate, the second factor was different weed interference periods consisted of five initial weed-free periods (in which, plots were kept free of weeds for 0, 15, 30, 45 and 60 days after crop emergence (DAE) and then weeds were allowed to grow until harvest) and five initial weed-infested periods (in which, weeds were allowed to grow for 0, 15, 30, 45 and 60DAE, after which the plots were kept free of weeds until harvest). Full season weedy condition reduced 100-seed weight, seed germination percentage and seedling dry weight by 25.9, 13.3 and 22.5%, respectively and increased mean germination time and seed electrical conductivity by 55.8 and 24.3%, respectively as compared with full season weed-free control. However, the traits under study were not significantly influenced when field was kept free of weeds for at least 45 DAE (R1) or weedy condition was continued for less than 30 DAE (V8). There was a significant and negative correlation between weed biomass and seed weight (r = -0.93), so that when weed free condition was less than 45 DAE or weed infested period was continued for at least 30 DAE, soybean plants produced wrinkled and underdeveloped seeds with lower weights and qualities. Moreover, soybean seed quality reduction due to weed interference was more evident when starter fertilizer was applied and weeds interfered with soybean from the beginning of the growing season. Information from the present study is beneficial in soybean seed production systems and where farmers use the harvested seeds for the following planting.

• Fire Science and Engineering
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• v.30 no.5
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• pp.93-99
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• 2016

This study tested the combustion characteristics of veneer specimens coated with four kinds of ammonium salts. Each veneer specimen was coated three times with 20 wt.% ammonium salt solutions at room temperature. After drying, the combustion characteristics of the specimens coated with chemicals, were investigated using the cone calorimeter (ISO 5660-1, 2). The specimens coated with monoammonium phosphate (MAPP) and, diammonium phosphate (DMPP) showed a 6.7% and, 10.0%, lower mean heat release rate ($HRR_{mean}$), respectively, than that of the uncoated specimen. On the other hand, the specimens coated with MAPP showed a 15.7% higher $CO_{peak}$ production rate and the specimens coated with DAPP showed by 8.2% lower rate than that of the uncoated specimen. The veneer coated with ammonium sulfate (AMSF) and DAPP showed a 9.6% and 33.3% lower the peak smoke production rate ($SPR_{peak}$) than that of the uncoated specimen. In addition, the time to the peak smoke extinction area ($SEA_{peak}$) was delayed by 38.4% in the specimens coated with DAPP than the uncoated specimen. Therefore, DAPP inhibited the combustion properties of the veneer and showed a tendency to reduce smoke production.