{"id":188,"date":"2009-03-24T03:39:59","date_gmt":"2005-04-15T16:18:22","guid":{"rendered":"http:\/\/vafs.dungnq.local\/2005\/04\/15\/nghien-cuu-xac-dinh-mot-so-tinh-chat-van-dam-go-bach-dan-nau-eucalyptus-urophylla\/"},"modified":"2019-09-25T09:52:46","modified_gmt":"2019-09-25T02:52:46","slug":"nghien-cuu-xac-dinh-mot-so-tinh-chat-van-dam-go-bach-dan-nau-eucalyptus-urophylla","status":"publish","type":"post","link":"https:\/\/vafs.gov.vn\/vn\/nghien-cuu-xac-dinh-mot-so-tinh-chat-van-dam-go-bach-dan-nau-eucalyptus-urophylla\/","title":{"rendered":"Nghi\u00ean c\u1ee9u x\u00e1c \u0111\u1ecbnh m\u1ed9t s\u1ed1 t\u00ednh ch\u1ea5t v\u00e1n d\u0103m G\u1ed7 B\u1ea1ch \u0111\u00e0n n\u00e2u (Eucalyptus urophylla)"},"content":{"rendered":"

Nguy\u1ec5n Tr\u1ecdng Nh\u00e2n<\/em><\/strong><\/p>\n

Vi\u1ec7n Khoa h\u1ecdc L\u00e2m nghi\u1ec7p Vi\u1ec7t Nam<\/em><\/p>\n

<\/h1>\n

B\u1ea1ch \u0111\u00e0n n\u00e2u(E. urophylla) <\/em>\u0111\u00e3 \u0111\u01b0\u1ee3c tr\u1ed3ng r\u1ed9ng r\u00e3i \u1edf nhi\u1ec1u n\u01a1i, nh\u01b0 \u1edf m\u1ed9t s\u1ed1 v\u00f9ng c\u1ee7a In\u0111\u00f4n\u00eaxia, Braxin v\u00e0 Nam Trung Qu\u1ed1c.<\/p>\n

\u1edf Vi\u1ec7t Nam, B\u1ea1ch \u0111\u00e0n n\u00e2u\u0111\u01b0\u1ee3c tr\u1ed3ng nhi\u1ec1u \u1edf Ph\u00fa Th\u1ecd, m\u1ee5c \u0111\u00edch ch\u1ee7 y\u1ebfu \u0111\u1ec3 l\u00e0m nguy\u00ean li\u1ec7u gi\u1ea5y. \u0110\u1ec3 l\u00e0m nguy\u00ean li\u1ec7u gi\u1ea5y, B\u1ea1ch \u0111\u00e0n n\u00e2u \u0111\u01b0\u1ee3c khai th\u00e1c \u1edf c\u1ea5p 8 tu\u1ed5i.<\/p>\n

V\u1edbi m\u1ee5c \u0111\u00edch m\u1edf r\u1ed9ng l\u0129nh v\u1ef1c s\u1eed d\u1ee5ng g\u1ed7 B\u1ea1ch \u0111\u00e0n n\u00e2u, <\/em>\u0111\u1ec1 t\u00e0i c\u1ea5p B\u1ed9 n\u0103m 2002 ti\u1ebfn h\u00e0nh nghi\u00ean c\u1ee9u \u1edf m\u1ee9c \u0111\u1ed9 th\u00ed nghi\u1ec7m nh\u1eb1m x\u00e1c \u0111\u1ecbnh m\u1ed9t s\u1ed1 t\u00ednh ch\u1ea5t v\u00e1n d\u0103m t\u1eeb nguy\u00ean li\u1ec7u g\u1ed7 B\u1ea1ch \u0111\u00e0n n\u00e2u.<\/p>\n

1. Qu\u00e1 tr\u00ecnh th\u1ef1c nghi\u1ec7m<\/strong><\/p>\n

1.1. <\/em><\/strong>Chu\u1ea9n b\u1ecb nguy\u00ean li\u1ec7u<\/em><\/strong><\/p>\n

Nguy\u00ean li\u1ec7u g\u1ed7 B\u1ea1ch \u0111\u00e0n n\u00e2u ph\u1ee5c v\u1ee5 nghi\u00ean c\u1ee9u \u0111\u01b0\u1ee3c l\u1ea5y t\u1ea1i Ph\u00f9 Ninh t\u1ec9nh Ph\u00fa Th\u1ecd v\u1edbi 2 c\u1ea5p tu\u1ed5i l\u00e0 6 v\u00e0 8 tu\u1ed5i. \u0110\u1eb7c \u0111i\u1ec3m c\u1ee7a g\u1ed7 nguy\u00ean li\u1ec7u \u0111\u01b0\u1ee3c ghi trong B\u1ea3ng 1.<\/p>\n

B\u1ea3ng 1. \u0110\u1eb7c \u0111i\u1ec3m g\u1ed7 E. urophylla l\u00e0m v\u00e1n d\u0103m <\/em><\/strong><\/p>\n\n\n\n\n\n\n\n\n\n
TT<\/strong><\/td>\nN\u1ed9i dung<\/strong><\/td>\n\u0110\u01a1n v\u1ecb<\/strong><\/td>\n6 tu\u1ed5i<\/strong><\/td>\n8 tu\u1ed5i<\/strong><\/td>\n<\/tr>\n
1<\/td>\n\n

T\u1ef7 l\u1ec7 v\u1ecf<\/h1>\n<\/td>\n

%<\/td>\n5.07<\/td>\n4.67<\/td>\n<\/tr>\n
2<\/td>\nT\u1ef7 l\u1ec7 gi\u00e1c<\/td>\n%<\/td>\n23.00<\/td>\n18.30<\/td>\n<\/tr>\n
3<\/td>\nT\u1ef7 l\u1ec7 l\u00f5i<\/td>\n%<\/td>\n71.93<\/td>\n77.03<\/td>\n<\/tr>\n
4<\/td>\nKh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch gi\u00e1c<\/td>\ng\/cm3<\/sup><\/td>\n0.48<\/td>\n0.51<\/td>\n<\/tr>\n
5<\/td>\nKh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch l\u00f5i<\/td>\ng\/cm3<\/sup><\/td>\n0.39<\/td>\n0.40<\/td>\n<\/tr>\n
6<\/td>\n\u0110\u1ed9 pH c\u1ee7a g\u1ed7<\/td>\n5.8-6<\/td>\n5.8-6<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

G\u1ed7 tr\u00f2n nguy\u00ean li\u1ec7u \u0111\u01b0\u1ee3c b\u0103m th\u00e0nh d\u0103m, khi b\u0103m, \u0111\u1ed9 \u1ea9m g\u1ed7 nguy\u00ean li\u1ec7u kh\u00f4ng th\u1ea5p h\u01a1n 60%. Sau khi b\u0103m, d\u0103m \u0111\u01b0\u1ee3c s\u00e0ng k\u1ef9 l\u1ea5y d\u0103m l\u1edbp trong v\u1edbi k\u00edch th\u01b0\u1edbc chi\u1ec1u d\u00e0y 0.1-0.3mm, chi\u1ec1u r\u1ed9ng 2.5-3mm, chi\u1ec1u d\u00e0i 10-15mm.<\/p>\n

D\u0103m kh\u00f4ng \u0111\u00fang k\u00edch th\u01b0\u1edbc \u0111\u01b0\u1ee3c \u0111\u01b0a v\u00e0o m\u00e1y nghi\u1ec1n \u0111\u1ec3 t\u1ea1o d\u0103m m\u1eb7t k\u00edch th\u01b0\u1edbc trung b\u00ecnh chi\u1ec1u d\u00e0y 0.1-0.3mm, chi\u1ec1u r\u1ed9ng 0.5mm, chi\u1ec1u d\u00e0i 1.5-2mm. Tr\u01b0\u1edbc khi phun tr\u1ed9n keo, d\u0103m th\u00ed nghi\u1ec7m \u0111\u01b0\u1ee3c s\u1ea5y kh\u00f4, \u0111\u1ed9 \u1ea9m l\u1edbp m\u1eb7t t\u1eeb 3\u00b84%, l\u1edbp l\u00f5i t\u1eeb 1\u00b82%.<\/p>\n

1.2. T\u1ea1o v\u00e1n th\u00ed nghi\u1ec7m<\/em><\/strong><\/p>\n

S\u1eed d\u1ee5ng keo urea-formadehyde l\u00e0m ch\u1ea5t k\u1ebft d\u00ednh \u0111\u1ec3 t\u1ea1o v\u00e1n d\u0103m th\u00ed nghi\u1ec7m. Keo c\u00f3 h\u00e0m l\u01b0\u1ee3ng kh\u00f4 48-50%, th\u1eddi gian ch\u1ea3y qua nh\u1edbt k\u1ebf BZ-4 h\u1ebft 25-30s, \u0111\u1ed9 pH c\u1ee7a keo 7-7.5. L\u01b0\u1ee3ng ch\u1ea5t x\u00fac t\u00e1c NH4<\/sub>CL chi\u1ebfm 1% so v\u1edbi keo.<\/p>\n

V\u00e1n th\u00ed nghi\u1ec7m c\u00f3 k\u00edch th\u01b0\u1edbc 5cm x 50cm x 1,5cm, c\u00f3 3 l\u1edbp, t\u1ef7 l\u1ec7 d\u0103m gi\u1eefa c\u00e1c l\u1edbp l\u00e0 20\/60\/20(%) l\u01b0\u1ee3ng keo l\u1edbp ngo\u00e0i 12%, l\u01b0\u1ee3ng keo l\u1edbp trong 8% so v\u1edbi l\u01b0\u1ee3ng d\u0103m kh\u00f4. D\u1ef1 ki\u1ebfn chi\u1ec1u d\u00e0y v\u00e1n th\u00ed nghi\u1ec7m s=”15-16mm,” kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch v\u00e1n 0.70g\/cm3<\/sup>, v\u00e1n kh\u00f4ng s\u1eed d\u1ee5ng ch\u1ea5t ch\u1ed1ng \u1ea9m. \u00e9pv\u00e1n \u1edf nhi\u1ec7t \u0111\u1ed9 140-145 0<\/sup>C, th\u1eddi gian k\u00e9o d\u00e0i t=”15″ ph\u00fat. S\u1ed1 li\u1ec7u v\u00e1n d\u0103m th\u00ed nghi\u1ec7m \u0111\u01b0\u1ee3c ghi \u1edf b\u1ea3ng 2.<\/p>\n

B\u1ea3ng 2. S\u1ed1 li\u1ec7u v\u00e1n d\u0103m th\u00ed nghi\u1ec7m<\/em><\/strong><\/p>\n\n\n\n\n\n\n\n\n
K\u00fd hi\u1ec7u v\u00e1n<\/strong><\/td>\nC\u1ea5p tu\u1ed5i c\u00e2y<\/strong><\/td>\nKh\u1ed1i l\u01b0\u1ee3ng TT v\u00e1n th\u00ed nghi\u1ec7m<\/strong><\/p>\n

(g\/cm3<\/sup>)<\/strong><\/td>\n

Lo\u1ea1i v\u00e1n d\u0103m<\/strong><\/p>\n

th\u00ed nghi\u1ec7m<\/strong><\/td>\n

\n
T\u1ef7 l\u1ec7 keo (%)<\/strong><\/h5>\n<\/td>\n
T\u1ef7 l\u1ec7 d\u0103m gi\u1eefa c\u00e1c l\u1edbp<\/strong><\/p>\n

(%)<\/strong><\/td>\n<\/tr>\n

L\u1edbp ngo\u00e0i<\/strong><\/td>\nL\u1edbp trong<\/strong><\/td>\n<\/tr>\n
B\u0110u6-70<\/td>\n6<\/td>\n700<\/td>\nV\u00e1n 3 l\u1edbp<\/td>\n12<\/td>\n8<\/td>\n20\/60\/20<\/td>\n<\/tr>\n
B\u0110u6-75<\/td>\n6<\/td>\n750<\/td>\nV\u00e1n 3 l\u1edbp<\/td>\n12<\/td>\n8<\/td>\n20\/60\/20<\/td>\n<\/tr>\n
B\u0110u6-70<\/td>\n8<\/td>\n700<\/td>\nV\u00e1n 3 l\u1edbp<\/td>\n12<\/td>\n8<\/td>\n20\/60\/20<\/td>\n<\/tr>\n
B\u0110u6-75<\/td>\n8<\/td>\n750<\/td>\nV\u00e1n 3 l\u1edbp<\/td>\n12<\/td>\n8<\/td>\n20\/60\/20<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

1.3.X\u00e1c \u0111\u1ecbnh t\u00ednh ch\u1ea5t v\u00e1n d\u0103m th\u00ed nghi\u1ec7m<\/em><\/strong><\/p>\n

Sau khi \u00e9p, v\u00e1n th\u00ed nghi\u1ec7m \u0111\u01b0\u1ee3c gi\u1eef 1 tu\u1ea7n \u1edf trong ph\u00f2ng v\u1edbi nhi\u1ec7t \u0111\u1ed9 350<\/sup>C, \u0111\u1ed9 \u1ea9m kh\u00f4ng kh\u00ed 80%.<\/p>\n

M\u1ed7i t\u1ea5m v\u00e1n th\u00ed nghi\u1ec7m c\u1eaft l\u1ea5y 5 m\u1eabu \u0111\u1ec3 th\u1eed \u0111\u1ed9 b\u1ec1n u\u1ed1n t\u0129nh, c\u00e1c t\u00ednh ch\u1ea5t kh\u00e1c m\u1ed7i lo\u1ea1i 5 m\u1eabu \u0111\u01b0\u1ee3c l\u1ea5y t\u1eeb ph\u1ea7n kh\u00f4ng b\u1ecb ph\u00e1 hu\u1ef7 sau khi th\u1eed x\u00e1c \u0111\u1ecbnh \u0111\u1ed9 b\u1ec1n u\u1ed1n t\u0129nh.<\/p>\n

M\u1ed9t s\u1ed1 t\u00ednh ch\u1ea5t v\u00e1n d\u0103m th\u00ed nghi\u1ec7m \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh d\u1ef1a theo ti\u00eau chu\u1ea9n GOCT 10632-70 c\u1ee7a Li\u00ean X\u00f4 c\u0169. S\u1ed1 li\u1ec7u trung b\u00ecnh m\u1ed9t s\u1ed1 t\u00ednh ch\u1ea5t ch\u00ednh c\u1ee7a v\u00e1n th\u00ed nghi\u1ec7m bao g\u1ed3m \u0111\u1ed9 b\u1ec1n u\u1ed1n t\u0129nh, \u0111\u1ed9 b\u1ec1n k\u00e9o vu\u00f4ng g\u00f3c v\u00e0 \u0111\u1ed9 d\u00e3n n\u1edf d\u1ea7y khi ng\u00e2m trong n\u01b0\u1edbc 24 gi\u1edd \u0111\u01b0\u1ee3c ghi \u1edf b\u1ea3ng 3.<\/p>\n

B\u1ea3ng 3. M\u1ed9t s\u1ed1 t\u00ednh ch\u1ea5t v\u00e1n d\u0103m th\u00ed nghi\u1ec7m<\/em><\/h4>\n\n\n\n\n\n\n\n
K\u00fd hi\u1ec7u v\u00e1n<\/strong><\/td>\nC\u1ea5p tu\u1ed5i c\u00e2y<\/strong><\/td>\nKh\u1ed1i l\u01b0\u1ee3ng <\/strong><\/p>\n

th\u1ec3 t\u00edch v\u00e1n (g\/cm3<\/sup>)<\/strong><\/td>\n

\u0110\u1ed9 b\u1ec1n <\/strong><\/p>\n

u\u1ed1n t\u0129nh<\/strong><\/p>\n

(MPa)<\/strong><\/td>\n

\u0110\u1ed9 b\u1ec1n k\u00e9o<\/strong><\/p>\n

vu\u00f4ng g\u00f3c <\/strong><\/p>\n

(MPa)<\/strong><\/td>\n

T\u1ef7 l\u1ec7 tr\u01b0\u01a1ng n\u1edf <\/strong><\/p>\n

chi\u1ec1u d\u00e0y khi <\/strong><\/p>\n

ng\u00e2m n\u01b0\u1edbc 24 gi\u1edd (%)<\/strong><\/td>\n<\/tr>\n

B\u0110u6-70<\/td>\n6<\/td>\n0.70<\/td>\n18.89<\/td>\n0.36<\/td>\n16.78<\/td>\n<\/tr>\n
B\u0110u6-75<\/td>\n6<\/td>\n0.75<\/td>\n19.92<\/td>\n0.39<\/td>\n17.23<\/td>\n<\/tr>\n
B\u0110u6-70<\/td>\n8<\/td>\n0.70<\/td>\n20.78<\/td>\n0.40<\/td>\n15.45<\/td>\n<\/tr>\n
B\u0110u6-75<\/td>\n8<\/td>\n0.75<\/td>\n21.22<\/td>\n0.44<\/td>\n16.65<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

2. K\u1ebft qu\u1ea3 v\u00e0 th\u1ea3o lu\u1eadn<\/strong><\/p>\n

2.1. \u0110\u1ed9 b\u1ec1n u\u1ed1n t\u0129nh<\/em><\/strong><\/p>\n

\u0110\u1ed9 b\u1ec1n u\u1ed1n t\u0129nh v\u00e1n d\u0103m g\u1ed7 B\u1ea1ch \u0111\u00e0n n\u00e2u ph\u1ee5 thu\u1ed9c v\u00e0o kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch v\u00e0 tu\u1ed5i c\u00e2y \u0111\u01b0\u1ee3c di\u1ec5n t\u1ea3 \u1edf s\u01a1 \u0111\u1ed3 1.<\/p>\n

Theo s\u01a1 \u0111\u1ed3 n\u00e0y, \u0111\u1ed9 b\u1ec1n u\u1ed1n t\u0129nh c\u1ee7a v\u00e1n t\u0103ng d\u1ea7n theo kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch, \u0111\u1ed3ng th\u1eddi t\u0103ng d\u1ea7n theo c\u1ea5p tu\u1ed5i.<\/p>\n

B\u1ea1ch \u0111\u00e0n n\u00e2u 6 n\u0103m tu\u1ed5i, kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch v\u00e1n 0.7g\/cm3<\/sup>,\u0111\u1ed9 b\u1ec1n u\u1ed1n t\u0129nh th\u1ea5p nh\u1ea5t \u0111\u1ea1t 18.89MPa. Kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch v\u00e1n 0.75g\/cm3<\/sup>, \u0111\u1ed9 b\u1ec1n u\u1ed1n t\u0129nh cao nh\u1ea5t \u0111\u1ea1t 19.92MPa.<\/p>\n

B\u1ea1ch \u0111\u00e0n n\u00e2u 8 n\u0103m tu\u1ed5i, kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch v\u00e1n 0.70g\/cm3<\/sup>,\u0111\u1ed9 b\u1ec1n u\u1ed1n t\u0129nh th\u1ea5p nh\u1ea5t \u0111\u1ea1t 20.78MPa. Kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch v\u00e1n 0.75g\/cm3<\/sup>, \u0111\u1ed9 b\u1ec1n u\u1ed1n t\u0129nh cao nh\u1ea5t \u0111\u1ea1t 21.22MPa.<\/p>\n

S\u01a1 \u0111\u1ed3 1. T\u01b0\u01a1ng quan gi\u1eefa \u0111\u1ed9 b\u1ec1n u\u1ed1n t\u0129nh v\u00e0 kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch<\/em><\/strong><\/p>\n

theo c\u1ea5p tu\u1ed5i c\u00e2y<\/em><\/strong><\/p>\n

2.2. \u0110\u1ed9 b\u1ec1n k\u00e9o vu\u00f4ng g\u00f3c<\/em><\/strong><\/p>\n

\u0110\u1ed9 b\u1ec1n k\u00e9o vu\u00f4ng g\u00f3c c\u1ee7a v\u00e1n d\u0103m g\u1ed7 B\u1ea1ch \u0111\u00e0n n\u00e2u ph\u1ee5 thu\u1ed9c tu\u1ed5i c\u00e2y v\u00e0 kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch v\u00e1n \u0111\u01b0\u1ee3c di\u1ec5n t\u1ea3 \u1edf s\u01a1 \u0111\u1ed3 2. Theo s\u01a1 \u0111\u1ed3 n\u00e0y, \u0111\u1ed9 b\u1ec1n k\u00e9o vu\u00f4ng g\u00f3c c\u1ee7a v\u00e1n t\u0103ng theo kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch v\u00e1n, \u0111\u1ed3ng th\u1eddi c\u0169ng t\u0103ng theo c\u1ea5p tu\u1ed5i c\u00e2y.<\/p>\n

B\u1ea1ch \u0111\u00e0n n\u00e2u 6 n\u0103m tu\u1ed5i, kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch v\u00e1n 0.70g\/cm3<\/sup>,\u0111\u1ed9 b\u1ec1n k\u00e9o vu\u00f4ng g\u00f3c th\u1ea5p nh\u1ea5t \u0111\u1ea1t 0.36MPa. Kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch v\u00e1n 0.75g\/cm3<\/sup>, \u0111\u1ed9 b\u1ec1n k\u00e9o vu\u00f4ng g\u00f3c cao nh\u1ea5t \u0111\u1ea1t 0.39MPa.<\/p>\n

B\u1ea1ch \u0111\u00e0n n\u00e2u 8 n\u0103m tu\u1ed5i, kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch v\u00e1n 0.70g\/cm3<\/sup>,\u0111\u1ed9 b\u1ec1n k\u00e9o vu\u00f4ng g\u00f3c th\u1ea5p nh\u1ea5t \u0111\u1ea1t 0.40MPa. Kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch v\u00e1n 0.75g\/cm3<\/sup>, \u0111\u1ed9 b\u1ec1n k\u00e9o vu\u00f4ng g\u00f3c cao nh\u1ea5t \u0111\u1ea1t 0.43MPa.<\/p>\n

S\u01a1 \u0111\u1ed3 2. T\u01b0\u01a1ng quan gi\u1eefa \u0111\u1ed9 b\u1ec1n k\u00e9o vu\u00f4ng g\u00f3c v\u00e0 kh\u1ed1i l\u01b0\u1ee3ng <\/em><\/strong><\/p>\n

th\u1ec3 t\u00edch theo c\u1ea5p tu\u1ed5i c\u00e2y<\/em><\/strong><\/p>\n

2.2. T\u1ef7 l\u1ec7 tr\u01b0\u01a1ng n\u1edf chi\u1ec1u d\u00e0y <\/em><\/strong><\/p>\n

T\u1ef7 l\u1ec7 tr\u01b0\u01a1ng n\u1edf chi\u1ec1u d\u00e0y c\u1ee7a v\u00e1n d\u0103m g\u1ed7 B\u1ea1ch \u0111\u00e0n n\u00e2u ph\u1ee5 thu\u1ed9c tu\u1ed5i c\u00e2y v\u00e0 kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch v\u00e1n \u0111\u01b0\u1ee3c di\u1ec5n t\u1ea3 \u1edf s\u01a1 \u0111\u1ed3 3. Theo s\u01a1 \u0111\u1ed3 n\u00e0y, \u0111\u1ed9 d\u00e3n n\u1edf d\u1ea7yc\u1ee7a v\u00e1n t\u0103ng m\u1ea1nh khi kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch c\u1ee7a v\u00e1n l\u1edbn, nh\u01b0ng gi\u1ea3m khi tu\u1ed5i c\u00e2y t\u0103ng. B\u1ea1ch \u0111\u00e0n n\u00e2u 6 n\u0103m tu\u1ed5i, kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch v\u00e1n 0.70g\/cm3<\/sup>, \u0111\u1ed9 d\u00e3n n\u1edf d\u00e0y cao nh\u1ea5t \u0111\u1ea1t 17.23%. Keo lai 8 n\u0103m tu\u1ed5i, kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch v\u00e1n 0.75g\/cm3<\/sup>, \u0111\u1ed9 d\u00e3n n\u1edf d\u1ea7y cao nh\u1ea5t \u0111\u1ea1t 16.65%.<\/p>\n

S\u01a1 \u0111\u1ed3 3. T\u01b0\u01a1ng quan gi\u1eefa t\u1ef7 l\u1ec7 tr\u01b0\u01a1ng n\u1edf chi\u1ec1u d\u1ea7y v\u00e0 kh\u1ed1i l\u01b0\u1ee3ng <\/em><\/strong><\/p>\n

th\u1ec3 t\u00edch theo c\u1ea5p tu\u1ed5i c\u00e2y<\/em><\/strong><\/p>\n

Trong ti\u00eau chu\u1ea9n ng\u00e0nh 04TCN2-1999, v\u00e1n d\u0103m lo\u1ea1i 1A, c\u00f3 chi\u1ec1u d\u00e0y l\u1edbn h\u01a1n 13cm, nh\u1ecf h\u01a1n 20cm, kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch t\u1eeb 0.50 \u0111\u1ebfn 0.85g\/cm3<\/sup> c\u00f3 \u0111\u1ed9 b\u1ec1n u\u1ed1n t\u0129nh l\u1edbn h\u01a1n ho\u1eb7c b\u1eb1ng 15MPa, \u0111\u1ed9 b\u1ec1n k\u00e9o vu\u00f4ng g\u00f3c b\u1ec1 m\u1eb7t v\u00e1n l\u1edbn h\u01a1n ho\u1eb7c b\u1eb1ng 0.35MPa.<\/p>\n

C\u00e1c lo\u1ea1i v\u00e1n d\u0103m g\u1ed7 B\u1ea1ch \u0111\u00e0n n\u00e2u 6, 8 n\u0103m tu\u1ed5i tr\u1edf l\u00ean, v\u1edbi kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch 0.7g\/cm3 <\/sup>v\u00e0 0.75g\/cm3 <\/sup>\u0111\u00e1p \u1ee9ng y\u00eau c\u1ea7u c\u1ee7a ti\u00eau chu\u1ea9n v\u00e1n d\u0103m lo\u1ea1i 1A theo ti\u00eau chu\u1ea9n ng\u00e0nh 04TCN2-1999.<\/p>\n

3. K\u1ebft lu\u1eadn <\/strong><\/p>\n

K\u1ebft qu\u1ea3 nghi\u00ean c\u1ee9u s\u1eed d\u1ee5ng g\u1ed7 B\u1ea1ch \u0111\u00e0n n\u00e2u 6, 8 tu\u1ed5i l\u00e0m v\u00e1n d\u0103m c\u1ee7a \u0111\u1ec1 t\u00e0i c\u1ea5p b\u1ed9 n\u0103m 2002 \u0111\u00e3 x\u00e1c \u0111\u1ecbnh, \u0111\u1ed9 b\u1ec1n u\u1ed1n t\u0129nh, \u0111\u1ed9 b\u1ec1n k\u00e9o vu\u00f4ng g\u00f3c, t\u1ef7 l\u1ec7 tr\u01b0\u01a1ng n\u1edf chi\u1ec1u d\u00e0y c\u1ee7a v\u00e1n ph\u1ee5 thu\u1ed9c v\u00e0o kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch c\u1ee7a v\u00e1n v\u00e0 v\u00e0o tu\u1ed5i c\u00e2y.<\/p>\n

\u0110\u1ed9 b\u1ec1n u\u1ed1n t\u0129nh, \u0111\u1ed9 b\u1ec1n k\u00e9o vu\u00f4ng g\u00f3c t\u0103ng theo kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch v\u00e1n v\u00e0 t\u0103ng theo c\u1ea5p tu\u1ed5i c\u00e2y. T\u1ef7 l\u1ec7 tr\u01b0\u01a1ng n\u1edf chi\u1ec1u d\u1ea7y t\u0103ng theo kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch v\u00e1n v\u00e0 gi\u1ea3m khi c\u1ea5p tu\u1ed5i c\u00e2y t\u0103ng.<\/p>\n

V\u00e1n d\u0103m g\u1ed7 B\u1ea1ch \u0111\u00e0n n\u00e2u 6 tu\u1ed5i, lo\u1ea1i v\u00e1n 3 l\u1edbp, ch\u1ea5t k\u1ebft d\u00ednh urea-formadehyde, keo l\u1edbp ngo\u00e0i 12%, keo l\u1edbp trong 8%, v\u1edbi kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch 0.70g\/cm3<\/sup>, 0.75g\/cm3<\/sup> \u0111\u1ea1t \u0111\u1ed9 b\u1ec1n u\u1ed1n t\u0129nh tu\u1ea7n t\u1ef1 18.89MPa, 19.92MPa, \u0111\u1ed9 b\u1ec1n k\u00e9o vu\u00f4ng g\u00f3c tu\u1ea7n t\u1ef1 \u0111\u1ea1t 0.36MPa, 0.39MPa. T\u01b0\u01a1ng t\u1ef1, v\u00e1n d\u0103m g\u1ed7 B\u1ea1ch \u0111\u00e0n n\u00e2u 8 tu\u1ed5i v\u1edbi kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch 0.70g\/cm3<\/sup>, 0.75g\/cm3<\/sup> \u0111\u1ea1t \u0111\u1ed9 b\u1ec1n u\u1ed1n t\u0129nh tu\u1ea7n t\u1ef1 20.78MPa, 21.22MPa, \u0111\u1ed9 b\u1ec1n k\u00e9o vu\u00f4ng g\u00f3c tu\u1ea7n t\u1ef1 \u0111\u1ea1t 4.08MPa, 4.37MPa. C\u00e1c lo\u1ea1i v\u00e1n n\u00e0y \u0111\u00e1p \u1ee9ng y\u00eau c\u1ea7u lo\u1ea1i v\u00e1n 1A trong ti\u00eau chu\u1ea9n c\u1ea5p ng\u00e0nh 04TCN2-1999.<\/p>\n

T\u00e0i li\u1ec7u tham kh\u1ea3o<\/strong><\/p>\n

1. Nguy\u1ec5n Ho\u00e0ng Ngh\u0129a-Ch\u1ecdn gi\u1ed1ng B\u1ea1ch \u0111\u00e0n Eucalyptus theo sinh tr\u01b0\u1edfng v\u00e0 kh\u00e1ng b\u1ec7nh \u1edf Vi\u1ec7t Nam, Nh\u00e0 xu\u1ea5t b\u1ea3n N\u00f4ng nghi\u1ec7p, H\u00e0 N\u1ed9i-2000.<\/p>\n

2. G.M.F. Vasman-s\u1ea3n xu\u1ea5t v\u00e1n d\u0103m nh\u00e0 xu\u1ea5t b\u1ea3n C\u00f4ng nghi\u1ec7p r\u1eebng, Matxcova-1987.<\/p>\n

3. Ti\u00eau chu\u1ea9n ng\u00e0nh 04TCN2-1999, v\u00e1n d\u0103m (\u0111\u1ecbnh ngh\u0129a, ph\u1ea1m vi \u1ee9ng d\u1ee5ng, ph\u00e2n lo\u1ea1i, ph\u01b0\u01a1ng ph\u00e1p x\u00e1c \u0111\u1ecbnh m\u1ed9t s\u1ed1 t\u00ednh ch\u1ea5t ch\u1ee7 y\u1ebfu, nh\u00e3n m\u00e1c, \u0111\u00f3ng g\u00f3i).<\/p>\n

Summary<\/h6>\n

6,8-year-old E. urophylla <\/em>was used as raw material of particleboard. Three-layered particleboards of target board-density of 0.70, 0.75g\/cm3<\/sup> were produced with urea formaldehyde resin. Bending strength (MOR), internal bond (IB) and thickness swelling (TS) satisfied the required properties of Type 1A of 04TCN2-1999. The readings of MOR, IB and TS of three-layered particleboards of 6-year-old E. urophylla <\/em>with target board-density of 0.70g\/cm3<\/sup> were 18.89MPa, 0.36MPa, v\u00e0 16.78%respectively, with target board-density of 0.75g\/cm3<\/sup> were 19.82MPa, 0.39MPa, v\u00e0 17.23%respectively. The readings of MOR, IB and TS of three-layered particleboards of 8-year-old with target board-density of 0.70g\/cm3<\/sup> were 20.78MPa, 0.40MPa, v\u00e0 15.45%respectively, with target board-density of 0.75g\/cm3<\/sup> were 21.22MPa, 0.43MPa, v\u00e0 16.65respectively. Consequently 6 and 8-year-old E. urophylla <\/em>may be a potential sourse of raw material for particleboards.<\/p>\n","protected":false},"excerpt":{"rendered":"

B\u1ea1ch \u0111àn nâu (E. urophylla) \u0111ã \u0111\u01b0\u1ee3c tr\u1ed3ng r\u1ed9ng rãi \u1edf nhi\u1ec1u n\u01a1i, nh\u01b0 \u1edf m\u1ed9t s\u1ed1 vùng c\u1ee7a In\u0111ônêxia, Braxin và Nam Trung Qu\u1ed1c. \u1ede Vi\u1ec7t Nam, B\u1ea1ch \u0111àn nâu \u0111\u01b0\u1ee3c tr\u1ed3ng nhi\u1ec1u \u1edf Phú Th\u1ecd, m\u1ee5c \u0111ích ch\u1ee7 y\u1ebfu \u0111\u1ec3 làm nguyên li\u1ec7u gi\u1ea5y. \u0110\u1ec3 làm nguyên li\u1ec7u gi\u1ea5y, B\u1ea1ch \u0111àn nâu \u0111\u01b0\u1ee3c khai thác \u1edf c\u1ea5p 8 tu\u1ed5i. <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[18],"tags":[],"_links":{"self":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/188"}],"collection":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/comments?post=188"}],"version-history":[{"count":6,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/188\/revisions"}],"predecessor-version":[{"id":19234,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/188\/revisions\/19234"}],"wp:attachment":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/media?parent=188"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/categories?post=188"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/tags?post=188"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}